GT40 / GT40P
Printed From: CorrectCraftFan.com
Category: General Correct Craft Discussion
Forum Name: Common Questions
Forum Discription: Visit here first for common questions regarding your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=34828
Printed Date: May-03-2024 at 9:20am
Topic: GT40 / GT40P
Posted By: john b
Subject: GT40 / GT40P
Date Posted: October-26-2014 at 4:35pm
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I have researched the GT40 and GT40P heads here and on several Mustang forums. There seems to be a general consensus that both of these heads flow better than the original heads on a 60s-70s 302. What is missing is a direct comparison with data in stead of "it feels much faster" seat of the pants assessment. By disregarding the posts I feel make outrageous HP claims and going with some of the Mustang (car) forums most reasonable people seem to believe that they offer a 20-40hp improvement on an engine with no other modifications, felt principally in the 1500-3500 rpm range. What is the opinion here? Does anyone know where dyno pull data can verify the claims made? I know there are a bunch of you out there running them including my favorite Mustang (the type with no wheels). I am also aware of some AFR heads that data shows substantial gains on a stock engine with no mods to the tune of around 90 HP on an 87 302 roller engine. I am also interested to know how comparable the straight plug geometry affects the exhaust fitment. It apparently works on my favorite Mustang. Thanx. ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Replies:
Posted By: Gary S
Date Posted: October-26-2014 at 9:56pm
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Got them on mine John,HM exhausts fit fine. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: john b
Date Posted: October-26-2014 at 10:20pm
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I know Gary. Yours was the Mustang I was referring to as my favorite. I don't remember if it was a tight fit or had plenty of room. I have been considering several options. I don't have a clear vision yet. I am up north right now and I am leaning toward bringing my spare H/M core and B/W Velve Drive home and sending it in for an overhaul and setting the one in the Mustang aside for now. If I do that I may go for a few non original things on the spare. Heads seem to provide the best ROI. The RR makes it impossible to upgrade to a roller cam. Just in the "what if" planning stage right now but I need to get moving. ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: TRBenj
Date Posted: October-26-2014 at 11:17pm
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Not impossible, just $$. P heads have been discussed ad nauseum here... Expect 40hp or so on a 351w. Add another 30-40 with the proper intake and cam to match. 302 numbers won't be quite as high... But a properly built p-headed 302 (cam and intake, 9.5-10cr) and you can approach 290hp or so. This is with the available RH flat tappets. Peak power usually ends up in the 5000-5200 range with a decent cam. Power is added everywhere, from holeshot on up. Gt40's are more highly regarded in automotive circles as they don't require special headers. Plug angle of the p's are an advantage on our upswept marine manifolds. In addition to slightly better flow, p's also have smaller chambers so they give you about a point of CR over the regular gt40's. Google "ford head flow chart" and you'll see flow numbers of stock e7's, gt40's, p's and many aftermarket heads. That's a better apples to apples comparison than dyno results since so many other aspects of a build can affect hp. Remember that you're limited to .490 lift with flat tappet RH stuff (and that's with 1.7's) so decent flow at lower lift is key. Don't be fooled by big flow numbers in the .500-.700 range as you'll never utilize it. |
Posted By: JoeinNY
Date Posted: October-26-2014 at 11:38pm
I hope you read that part carefully cause too much time on some of them car websites can rot the brain. The spark plug location on the GT40p is an improvement over every stock ford head I have seen used in a marine application. They actually become easier to access... I also second that they have been discussed here in the past quite extensively... likely more in depth than anything else you can find on the web. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
TRBenj wrote:Posted By: john b
Date Posted: October-27-2014 at 12:13am
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Thank you Tim. I googled correct craft fans Gt40>40P and read everything that came up. I may be willing to give up the stock manifold on the "spare" but I believe I am am staying with the original flat tappet cam. It concerns me that it raises the CR 1 point since it is 10.5:1 right now. I want to be able to use the 91 marine gas available on my chain. I saw that there is a source out there that some recommended. I would have to rebuild the stock heads anyway so it seems like it would be pretty economical. Do you have any more suggestions. I know some purists may not like it but I can set aside the old heads from this one and store the original engine. ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: TRBenj
Date Posted: October-27-2014 at 12:27am
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Pete will clarify but I don't believe even the ACBS frowns upon head changes. I know that internal engine changes are ok without a point deduction. Early (pre 73) H-M is the exception when it comes to sbf marine longblocks. All others had mid 8 cr's and p's bring them to mid 9's. I am not certain how HM got to 10.5:1 (pistons vs chambers) but if anyone knows off the top of their head it would be Reid or Gary. Mr Starr will have to remind us how much of the engine he rebuilt. 10.5:1 is as far as id push it on 91 or even 93. |
Posted By: john b
Date Posted: October-27-2014 at 1:02am
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I believe my shop guy said it has teeny chambers. Are you familiar with these? http://www.airflowresearch.com/index.php?cPath=21_106" rel="nofollow - AFR 165cc non smog ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: Gary S
Date Posted: October-27-2014 at 1:43am
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Don't forget guys mine is far from when it left Correct Craft. It started out as a 200hp 2v 9.3cr 289. Somewhere along the line the block was replaced with a 302. I used TriStates heads that have the same chamber size as the 70's heads they replaced. In my haste to get it running with the new heads I did not measure the cc's of the cylinder at tdc so I don't know what my cr ratio is. I am using flat top pistons with a .030 overbore. When I replaced my heads I used ARP cylinder studs and did run into minor clearance issues with the exhaust manifolds,but a minor touch up with a dremel solved that issue ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: john b
Date Posted: October-27-2014 at 2:39am
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Gary, did the heads of the ARP bolts hit the manifolds? How much relief was required to make them fit? ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: TRBenj
Date Posted: October-27-2014 at 8:05am
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By all accounts, AFR makes some nice heads. Better than the p's for sure but at nearly 4x the cost, they better be! Rhs and trickflow, as well as many others, make good heads too. I can't speak to best bang for the buck in terms of aftermarket, but the p's are going to be tough to beat when it comes to hp/$. If you go aftermarket aluminums, it's not a bad idea to buy them from a reputable shop that has gone through them and set them up properly. Joe, did you work through Jay Allen with your Trick Flows? An aluminum head will certainly be easier to spot if you're trying to keep the "look" somewhat stock- something to keep in mind. |
Posted By: JoeinNY
Date Posted: October-27-2014 at 8:53am
http://www.totalengineairflow.com" rel="nofollow - total engine airflow Did the original bowl work and assembly. They also welded them up after the digested a piece of.the number on piston. Quality and timely work. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: 8122pbrainard
Date Posted: October-27-2014 at 9:46am
Tim, You are correct. As an example, many Chris marines have had a 350 block exchange. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Gary S
Date Posted: October-27-2014 at 10:43am
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John clearance issues were minor,depending on how the nut was clocked after it was torqued determined if clearancing was needed. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: john b
Date Posted: October-28-2014 at 3:10pm
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Thank you Tim, Gary, Pete and all who helped. I was losing my way a bit and you put me back on track. I talked to Tri State. $598.00. and they install the larger valves. I just need to determine my current chamber size now so I don't exceed what I view as the limit of 10.5:1 that it is now. ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: JoeinNY
Date Posted: October-28-2014 at 3:25pm
Be careful on the spring selection through- ask them if they are ok to use with a flat tappet cam and if there is anything special you should do during cam break in. You can always lower compression with your head gasket selection, although it can get more expensive to specify a fancy cometic gasket with a custom size. You may need to figure out which pistons you have and do the math rather than try and go backwards from what you think the last setup was rated at. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: john b
Date Posted: October-28-2014 at 4:11pm
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Thanks Joe. Good points. He should understand that it is a flat tappet, I told him it was a 69. If I go with my spare core, which I am considering now, the pistons will have to be hammered out so I will have a fresh set up of known parts. If possible I will probably have the shop reuse the cam and lifters unless someone has a much better idea for the cam. I like the lopey idle. The core was originally a 210HP 2V H/M but was changed to a 4V using the correct manifold by casting # at some time. I have no idea if it used the same cam as the 235hp4V H/M that is in my Mustang now. Do you have a suggestion for a cam with good performance while retaining low end torque? "Decoy" looks fast to me. Although I love them, I am not looking to build one like your SN or Tim's barefoot. ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: TRBenj
Date Posted: October-28-2014 at 4:43pm
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The current crop of available RH blanks are limited to .460 lift at the valve (with stock 1.6 rockers). This cam is about the only flat tappet RH I would consider changing to. Reid is probably the only person who might be able to tell you how that 2v HM cam spec'd out. I would guess it's kinda small, being for a 210hp 2bbl, but that's just a guess. 1.7 rockers might be a consideration instead if a cam swap is deemed unnecessary. I would call tristate back and see what they say about the sprigs. Iirc, they are on the aggressive side ("up to .550 lift") and you will want to reiterate that you have a flat tappet- and are considering a new flat tappet so break in may be a concern. Wiped lobes are the worst! |
Posted By: Bri892001
Date Posted: October-28-2014 at 4:54pm
| When you guys say 2v and 4v, what are you referring to? Just trying to follow. |
Posted By: MrMcD
Date Posted: October-28-2014 at 5:13pm
| Sealed Power still sells the Marine grind cam for the 302, gives a lot of low end torque but has good idle quality. I put one in a friends 68 (4 wheel) Mustang with an automatic trans and tall gears and it ran really well all the way to 5,300 RPM or so. He is very happy with that selection. It is a copy of the grind Pleasure craft used for the 302. I believe they have it RH and LH rotation. I am sure you can get more cam but you may need a custom grind. Reverse rotation limits what is available. |
Posted By: TRBenj
Date Posted: October-28-2014 at 5:31pm
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2bbl and 4bbl, Brian. Mark, got a link to those cam specs? RH stuff is in low supply these days. Custom (flat tappet) grinds don't cost any more in my experience, but the current limitation is the blank they're working with. If someone has some older (wilder) stuff on the shelf somewhere, I'd love to know! The PCM stuff was in fact pretty tame... I wouldn't bother "upgrading" to one of those, especially from a HM. I'd need a measurable performance benefit to justify the upgrade- and I assume that's what John is looking for. |
Posted By: john b
Date Posted: October-28-2014 at 5:34pm
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Hi Bri892001. 2V and 4V refer to the carburetor venturis, commonly called "barrels". The 210hp H/M engine, iirc is a 450 cfm 2V, and the 235hp H/M used an Autolite 600cfm 4V. Just a wild guess but I think the 210 probably had more low end torque than the 235 4V, especially since the Autolite was mechanical and not a progressive linkage. It could dump all the vacuum at the flick of a wrist. I'm not an expert but the original 4V doesn't seem well suited to a ski boat to me. ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: Bri892001
Date Posted: October-28-2014 at 7:37pm
Got it, v for Venturi, not for Valve 
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Posted By: TRBenj
Date Posted: October-28-2014 at 7:44pm
John, I'm not at all familiar with the autolite carbs... But maybe you could explain why you think the 4v might have been a poor performer (at least out of the hole)? The only boat I've ever seen where you need to be judicious about applying too much throttle out of the hole was Reid's warmed up Royal Flush... In 2bbl form. |
Posted By: john b
Date Posted: October-28-2014 at 9:39pm
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The Autolite C8AF-AE 4100 is a strange bird. From what I can tell it was installed only on the Shelby GT500 (428), 428 police interceptor, Holman Moody race cars, and possibly on a few 390 Tbirds. I have found little on its flow but I have read some think it was as high as 750CFM, which would seem about right for 428 displacement. Since it is installed on a 302 I am assuming ( just a guess here ) that it is more than adequate for a 302 and any benefit would be in the higher RPM range. The linkage opens all 4Vs in unison. It has been my experience that an over carbureted engine suffers somewhat at lower rpm since the vacuum drops almost instantaneously and the fuel/air velocity decreases causing less efficient flow and atomization. This effect is noticable when changing from a dual plane intake to a single plan. Do you agree or think I am way off base? Don't think you will offend me if you don't agree. I got a ride in your boat. ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: 63 Skier
Date Posted: October-28-2014 at 11:13pm
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That's the first time I've heard of a carb that opens all 4 barrels together. I wonder what the thought process was behind it? Maybe avoid the possible hesitation of secondary's that kick in later? ------------- '63 American Skier - '98 Sport Nautique |
Posted By: TRBenj
Date Posted: October-29-2014 at 12:01am
| I follow your logic john... Seems like what you're describing is essentially a real big 2bbl! |
Posted By: john b
Date Posted: October-29-2014 at 4:26am
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Dave, my guess is it may be because the cars the C8AE-AF Autolite was installed on were generally either not sold to the general public ( Police Interceptor ) or they were not built by Ford (Shelby GT500 and Holman Moody 428) and little thought was given to anything but driving with the loud pedal down. At high rpm power settings I believe this configuration would offer better throttle response and it would be more linear. I'm a hack skier and all I like is a hard smooth pull out of the hole, not instant response at 3000rpm. Is there any use for that in a ski boat? I don't know, I'm just an over the hill hack skier. In the interest of safety I'm not going to use the Autolite, it's not a marine carb. I have a marine Holley 600 that's going on there. ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: MrMcD
Date Posted: October-29-2014 at 6:46am
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The Sealed Power Part number for Reverse Rotation Marine Camshaft is CS-1057M uses firing order 18456273. It has .444/.452 lift and 115 lobe separation. Not a high performance cam but a good strong RV type grind. Pulls hard. Works good in boats. I checked on FMECAT.com and the part number is listed but it shows DISCONTINUED. Sorry for offering hope. Clevite or Elgin may still offer a version of this cam. You could go to a local Cam Grinder and regrind your old cam to the specs you want. Reground Cams are actually a 100% fix if the right guy does the work and they can modify the grind for you if desired. usually less than $100 for this work. |
Posted By: MrMcD
Date Posted: October-29-2014 at 6:48am
| If anyone is interested I saw a listing for GT40 heads used on Craigs List Sacramento. $200. for the set. Probably need a valve job after purchase but a good find for someone. |
Posted By: MrMcD
Date Posted: October-29-2014 at 7:05am
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Elgin Part # E870S,351W Rev Rotation part number. Elgin has been around forever in Engine Parts. Another name I forgot carries camshafts is Melling. Same company supplies Oil Pumps. Just a couple brands to check for supply. These names are suppliers of Parts, most engine parts houses will have them available, may need to order them in but that is usually 2-3 days travel time and you can have the part. |
Posted By: 8122pbrainard
Date Posted: October-29-2014 at 9:45am
Some do feel they are tubing boats!   ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: john b
Date Posted: October-29-2014 at 12:50pm
Thank you Pete. I will ask for the "tubing profile" if I order a cam.  ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: 8122pbrainard
Date Posted: October-29-2014 at 1:10pm
I'd say ask them for a mid range RPM cam!  ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: TRBenj
Date Posted: October-29-2014 at 2:09pm
I would discourage saying any such thing to a cam guy! |
Posted By: Tim D
Date Posted: October-30-2014 at 12:38am
I put a Clevite came in my Mustang. It changed the firing order to that of a 351. Roller rockers made a big difference in the mid-range power.   ------------- Tim D |
Posted By: john b
Date Posted: October-30-2014 at 1:02am
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That's really sweet looking. Do you know the rocker ratio? I am of the understanding that the lift is limited to >.5 with the heads I want. ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: TRBenj
Date Posted: October-30-2014 at 5:13am
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John, you are not "limited" to .500 lift with p-heads... They just don't flow significantly more at higher lift in stock form (Google gt40p head flow data and you'll see what I mean). They're a very good stock replacement head but they do have their limitations. They are probably not a good choice for BIG power (>1hp/ci) given the rpm range we tend to run (5k or so). That said, they're a great choice for a mild build. Even going with the "biggest" RH cam currently available (cam researches popular .460 grind) and the biggest rocker ratio (1.72) and you won't quite reach .500 at the valve. I'd say you would be happy with 1.6's- my uncle built a p-headed 302 for his ski Tique with that cam (stock 1.6 rockers) and the dyno said the combo was good for 290hp or so. It pushes the boat 54-55, it's quite the little rocket. |
Posted By: john b
Date Posted: October-30-2014 at 11:33am
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Tim, would that be 56.4 to be exact? That is very impressive. Very pretty boat too if it's the one I think. Does it have the stock intake? That sounds like just what I'm looking for if it has descent manners for putting around and the wife & kids to use. ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: TRBenj
Date Posted: October-30-2014 at 11:59am
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Yes, it hit 56.4 with a little stainless 2-blade, about 1mph better than the Acme 1210 could muster. It has an edelbrock performer rpm intake on it, if I remember correctly. It's very well behaved... As are all modified correct crafts I've encountered thus far. Even Joe's 83 and our bfn start reliably and idle nicely down at normal rpm's (650ish). The bfn sounds lumpy with the 4" exhaust and big cam, but it is perfectly functional for putting around and pulling skiers, which is it's primary purpose. It just goes faster when the throttle is pushed further. You'd really have to build an extreme motor, or at least be mighty careless in component selection to diminish overall usability of these boats. They're very light and with prop slip essentially have the equivalent of high stall torque converters, so there's no need to be concerned with a potential drop off in "off idle" power, unlike a heavy muscle car. I've never seen an engine built with midrange to high end power in mind that also didn't improve holeshot (usually significantly). I think people are generally too conservative, as remarks like "build for low end power" or "water tractor" are pretty common- and only serve to limit your options (with no benefit). |
Posted By: phatsat67
Date Posted: October-30-2014 at 12:46pm
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Mmmm water tractor.. Well behaved??? I think the Tique is a little unruly when it starts to bounce ;). ------------- |
Posted By: gun-driver
Date Posted: October-30-2014 at 2:51pm
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John, If you decide to go with stud mount roller rockers I have a set of 1.6 Scorpions I would be willing to sell. I only put a couple of test hours on them before I changed them for a set of 1.7s http://s256.photobucket.com/user/gun-driver/media/85%20boat%20rebuild/IMG_0633.jpg.html" rel="nofollow"> 
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Posted By: TRBenj
Date Posted: October-30-2014 at 3:29pm
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What heads are you running studs on, paul? It's significant $$ to convert from pedestal mount just for the one time adjustability, though it is nice. I'd advise sticking with pedestals on a factory head... Probably not worth the extra cost at the relatively tame power levels factory iron heads will be pushing. Aftermarket heads, studs all the way! |
Posted By: gun-driver
Date Posted: October-30-2014 at 3:40pm
| Those are the heads I have on the '85s RR motor. Do0E mildley ported with bigger valves. |
Posted By: Gary S
Date Posted: October-30-2014 at 6:03pm
Here is a flow comparison chart I have from a long time ago ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: 81nautique
Date Posted: October-30-2014 at 6:05pm
Those are 79 nautiques old heads. |
Posted By: gun-driver
Date Posted: October-30-2014 at 7:13pm
| Yes with a little more work. |
Posted By: Tim D
Date Posted: October-30-2014 at 11:29pm
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My rollers are 1.6. They will required taller valve covers, which are very close to the exhaust manifolds. ------------- Tim D |
Posted By: TRBenj
Date Posted: October-30-2014 at 11:36pm
| Not all roller rockers require taller valve covers. I'm running pedestal mount 1.6 FMS (crane) rr's under stock height valve covers on my '90. |
Posted By: Tim D
Date Posted: October-31-2014 at 12:35am
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True, mine are on studs and those '66 valve covers were very small. ------------- Tim D |
Posted By: john b
Date Posted: November-07-2014 at 4:16pm
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Does anyone have any thoughts on this manifold? My guess would be that it doesn't offer much performance increase but I like the look. It is obviously taller than the original iron manifold and clearance may be an issue. http://www.holmanmoody.com/Intakes1.html" rel="nofollow - Aluminum dual plane ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: TRBenj
Date Posted: November-07-2014 at 5:27pm
| I want to say Reid is running one on his 347 '73 HM. Similar to a performer rpm iirc, the extra $ might be worth tj for the look! |
Posted By: john b
Date Posted: November-07-2014 at 6:21pm
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Thanks Tim. I am reasonably certain I will set aside the good original engine and start fresh with the spare and add some bling. I just got an email from Lee Holman informing me that the out of stock H/M valve covers like Gary's are expected to be back in stock within the next couple of weeks. I need a distributor recommendation for it too since I am not opposed to mixing it up with the spare. I will add it up when I have a list of everything I think I need, heads, cam, rockers, intake, distributor, pistons, rebuild, and maybe a 331 kit, and make a decision. It may still come in at less than the tax on a new CC. How plans change. I should get my refurbished H/M manifolds back within the next two weeks. ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: MrMcD
Date Posted: November-07-2014 at 7:31pm
| If you are building a new engine why not find a 351W and build it rather than stroke a 302. I think you could make more power and do it for less money. Or stroke the 351W and make even more!!! Power always brings smiles in boats. |
Posted By: 81nautique
Date Posted: November-07-2014 at 7:38pm
Sounds logical at first but it has to fit under the doghouse? |
Posted By: Hollywood
Date Posted: November-07-2014 at 8:04pm
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Get a bigger doghouse! ------------- |
Posted By: Gary S
Date Posted: November-07-2014 at 8:57pm
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Get an upholstered wood one ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: MrMcD
Date Posted: November-08-2014 at 6:07am
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I know the 351W is slightly larger, Are the old dog houses that tight? A little quote from the internet, "Here’s even more cool stuff about the 351W: It is only 1” wider (approximately), and 1” taller than a 289/302 and almost all of the outer bolt-on’s are the same, from the motor mounts, to the valve covers, to the water pump, to the bell housing bolt pattern, to the exhaust bolt pattern, to the spark plugs, to the heads, rockers, timing cover and so on….. all the same as ANY 289/302. Put a 289 / 302 side by side with a 351W and take a few steps back. It’s VERY hard to tell the difference between the two. The best part is; it’s a completely bolt-in swap for any early Mustang from 65 on-up, and any early Falcon, Galaxie, Fairlane, Cobra kit car, 5.0 Mustang, or pretty much anything that had a 289/302 sitting in it. Usually all it takes to swap out a 351W with a 289/302 is nothing more than a set of retro fit headers and a low profile air cleaner and you’re good to go. Hedman makes a great set of retro fit headers for early Mustangs, Falcons, etc.. So, without even spending any extra money on expensive stroker parts, a stock 351W has a MUCH stronger block and lower-end, a better deck height, and a better rod angle without even doing a thing to it, plus it is already larger in displacement than both the 331and 347 strokers! Remember that saying? “There’s no replacement for displacement”? Right from the get-go it’s bigger and it’ll make more power, plus it’ll handle that additional power MUCH better (and much more of it) than ANY 289/302 based stroker ever will! Now here’s an even better part. One of the best all around strokers you can build is a 408 cubic incher based on a 351W block. So consider this, you can either spend all of your money building a weak little 331 or 347 stroker, or you can build a nice 351W and turn it into a monster 408 cubic incher for about the same amount of money, which will absolutely eat-up and spit out the other two on ANY given day!" The 351W uses a much longer connecting rod, this takes a lot of stress out of the engine with less piston side wall loading and helps with durability. |
Posted By: 81nautique
Date Posted: November-08-2014 at 11:36am
No debate on what you copied from the Internet but isn't it a known issue that the 351 doesn't fit and is a major reason guys stroke the 302? I have never worked on a little mustang so I'm really just making conversation but I think the guys that know these boats would add some fact. And by guys that know these boats I don't mean Hollywood. |
Posted By: Gary S
Date Posted: November-08-2014 at 12:06pm
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We should measure the width and length of a wood vs a 'glass box. I only have about 1/4 to 1/2 side clearance on mine til the manifolds hit. Not sure if PCM's are narrower,I suspect they are,but in my case I sure would not give up the HM's just so I could have a 351. Maybe those squared off newer style ones,like the one John has would clear better,I don't know. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: john b
Date Posted: November-08-2014 at 3:14pm
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Thanks for the input everyone. I have been following the "Custom 1965 Correct Craft Mustang Build" thread and enjoy it, but I am not looking to build a restomod. I am only considering this engine work because I have a spare H/M engine that's locked up and it would be nice to have a fresh engine. I work slowly and I don't want to make more work for myself. I also want it to look all original, at least with the motor cover down, and I NEED it ready before Green Lake next summer. The engine work requires nothing from me other than dropping it off at my engine shop and picking it up fresh and detailed. The original engine runs good and I can set it aside complete with all the correct pieces. I suspect my spare tranz is probably just a core and that they are not worth much if anything in that condition. I plan on re-using the original. There is plenty to do without making more work for myself. This boat will be used by my wife and kids and I don't want it to be more than they can handle. I sold my last boat for exactly that reason If this Mustang is capable of a deep water barefoot start (not for me) and looks good with a few old cotton tops in it, it is good enough for us. I don't intend to show it, Gary has that base covered. ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: Hollywood
Date Posted: November-08-2014 at 3:54pm
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I am pretty sure Tim knows what boxes fit what. ------------- |
Posted By: TRBenj
Date Posted: November-08-2014 at 7:47pm
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I do. The '69.5+ flat top boxes fit over 351's as the same box was used on most boats (ski nautiques included) through '82. The curvier boxes used prior to that will not fit a 351 underneath unless the manifolds are very conservative and even then questionable. Wood boxes came over the wider chryslers and even 302 HM's. Most people who know engines half way decent would spot a 351w in place of a 302, the width is pretty easy to spot. With the power levels being discussed here, no reason to step up to the larger block. For a 400+ hp build, I'd think differently. |
Posted By: Gary S
Date Posted: November-08-2014 at 8:11pm
Yea like I'm not wasting a 400 + engine on a 16 foot Mustang ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |