Torque & HP Open Discussion |
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Andy
Senior Member Joined: July-27-2008 Location: M'boro, TN Status: Offline Points: 382 |
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I got my newest issue of Hot Rod mag tonight. Page 92 in big letters it reads "351 hop-up". They are stating 54 rear wheel horsepower with the Edelbrock top end "kit". It consists of Performer RPM XT heads, 1.6:1 roller rockers (crane parts,not included in the kit), Performer RPM intake, Performer link timing set, Rollin Thunder Cam, Edelbrock hydraulic roller lifters, and a shorter pushrod length.
Their dyno sheet showed 303.29 rwhp at 5700 RPM. |
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5768 |
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Thought I would repost these photos over here.
Still planning on doing some basic flow tests but I think that won't happen until January when I get a little free time. It will take me until then to complete the refurbishing of my HM manifolds anyway. The new heads shipped yesterday so I'm anxiously waiting for them to arrive. I'll post some pics and flow data once I get it then start pulling things apart after the first of the year. |
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You can’t change the wind but you can adjust your sails
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Waterdog
Grand Poobah Joined: April-27-2006 Location: United States Status: Offline Points: 2020 |
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Alan
I'm looking forword to seeing a picture of the exhaust ports. I talked to Scott at cam research and some other guys before I ported my GT 40p's. I think I got pretty close to what was recomended (for working this head for the first time). |
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JoeinNY
Grand Poobah Joined: October-19-2005 Location: United States Status: Offline Points: 5693 |
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I did pull my hiteks and commanderstyle the other day if anyone wants them for testing purposes let me know.
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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Joe - Don't send your hiteks to 81 Nautique, otherwise we might get to see what's inside them too!
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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Andy
Senior Member Joined: July-27-2008 Location: M'boro, TN Status: Offline Points: 382 |
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So heres a newB question for ya. When purchasing a cam can I get any cam advertised or is there a rot specific note I need to look for, or a specific place I should call, or a magic troll to put under my timing cover?
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Waterdog
Grand Poobah Joined: April-27-2006 Location: United States Status: Offline Points: 2020 |
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Andy
Give Cam Research a call 303-762-0022 There Ford guys. My reverse rotation (ski boat grind) cam & lifters was about $250. |
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Brktracer
Senior Member Joined: December-20-2007 Location: South Carolina Status: Offline Points: 387 |
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Comp cams can grind you one also. I think any specs other than stock will have to be custom ground.
Joe, I would love to try the manifolds but I have a big problem. Our lake is down about 25' now due to the drought. Tree tops are starting to poke up in various places so there's no way I'm taking the Nautique out. I would love to do some testing but can't until we get some serious rain! It's not looking good for this summer! Matt |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21115 |
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You'll find many Cam Research endorsements here. JoeinNY, Boat Dr, Alan (81Nautique), and myself all have used them in our boats. They only do Fords and they know their stuff. I think I was the first here to find them, but they had already done cams for a lot of ski boats. See if Comp or Crane even know what a Ski Nautique is! Before you call them, you'll want to have some details on hand. They'll need specific info on your other engine components (heads, intake, compression ratio, etc), and obviously need to know whether or not you have a reverse rotation motor in order to make a good recommendation. That $250 number sounds about right- and that price should include the break-in service that they offer. |
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Andy
Senior Member Joined: July-27-2008 Location: M'boro, TN Status: Offline Points: 382 |
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Thanks guys!!
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5768 |
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The new heads came back from Cam Research today. We bought bare castings and had them ported, angle milled for smaller cc chamber, 5 angle valve job and they installed springs to match my cam and rpm operating range.
The old heads in the photos are stock castings from the original 81 engine before the rebuild, the gt40p are still on the boat for now. Enjoy!!! |
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You can’t change the wind but you can adjust your sails
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Andy
Senior Member Joined: July-27-2008 Location: M'boro, TN Status: Offline Points: 382 |
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Holy holes there magicman!!!
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Waterdog
Grand Poobah Joined: April-27-2006 Location: United States Status: Offline Points: 2020 |
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Bump to the top
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5768 |
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Funny you bumped this Waterdog, I finally got some time this weekend to gasket match the intake to the new heads. Needed to remove lots of material but they came out pretty good. The factory port castings are not very uniform and even if they matched up good enough they could use to have some of the casting lines removed so I've cleaned up as deep into the ports as I can get. I still have some drum sanding to do but the heavy work is done. Took about 4 hours to do the intake.
Exhaust manifolds are coming back from the machine shop later this week after having all mating surfaces machined. I'll gasket match them next. Biggest problem I see there is I don't think I'll be able to open them up enough to match the ports on the heads so the exhaust is still somewhat of an issue. Needed to remove almost an 1/8" of material Partially completed port matching |
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You can’t change the wind but you can adjust your sails
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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Allen taper the cut when you do the exhaust, The flange is thick enough and it's much better to have a transition than a flat wall, think of it as adding a chamfer all around. Depending on how much needs removed and how deep you can go will drive the angle.
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5768 |
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That's the plan Chris, problem is I'm switching over to Holman Moody manifolds and they are water jacketed all the way down to the block so there's just not much material fro removal and I'm concerned about cutting through. I'll go as far as I dare and then taper. Thanks |
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You can’t change the wind but you can adjust your sails
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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well that would be the first ones to do that because to do that then you also have to have the jacket around the mounting bolts and I doubt that they are. There should be plenty of wall thickness in the runners that mount to the heads, you don't need to open them up all of the way to the common passage just create a nice smooth transition and 1/2"-1" is more than enough |
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5768 |
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Lousy picture but all I have here on this computer. The arrows indicate the area on the bottom of the manifolds where the ports are water jacketed all the way to the head. Although I'm not sure how much I will have to remove yet I'll have to be careful, that's all.
The thickness of material between the bolt holes and the port "should" allow for a fair amount of opening but the stock ports on the HM and PCM manifolds are so much smaller than on these heads that I will have to settle for a happy medium. These ports are really designed for a nice set of headers but I'll make it work. |
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You can’t change the wind but you can adjust your sails
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MaddMarxx
Platinum Member Joined: June-29-2006 Location: United States Status: Offline Points: 1741 |
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Alan..Those heads look great, your Boat is going haul butt with them on it, What do they cost? And are you going to run the same Cam you are using now?
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5768 |
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Mark, You can buy them assembled from Summit for less than $1000 but I got them bare through Cam research and had him do some porting and we milled them to get my compression up. He then did a 5 angle valve job and matched the springs to my cam. The porting wasn't mandatory but he talked me into it and I'm glad he did, he does very nice work. Take a look at the area around the valve guides compared to stock heads, it's amazing how much work went into that area to get it looking that nice. These same heads are available in aluminum if you want to go that route. I am staying with the cam that was in the boat, after installing the 1.7 roller rockers it will be at .488 lift. If I was starting from scratch I would change the cam out but I think this will be a runner as is. |
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You can’t change the wind but you can adjust your sails
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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Allen I'm not so sure that the water jacket extends to the extent that you say it really doesn't appear that there is enough wall thickness for there to be a water jacket around them maybe on the backside in between the bolts could be a small pocket but theres no way it's all around the port. More like a straight cyclindrical shape otherwise the core needed for the casting to make the cavity doesn't make since and gets to thin and would never hold togther when the aluminum was poured in the mold.
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5768 |
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I wish I had them in front of me to take a look as I'm going from memory, I should have them back this weekend but you're probably right. I tend to be over-cautious with first time projects so I'm sure I'm over planning something that's fairly routine. Thanks for the help, I'll post some better pictures once I get going on them. I have the polishing just about done too, they certainly don't look like the above photo anymore.
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You can’t change the wind but you can adjust your sails
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Brktracer
Senior Member Joined: December-20-2007 Location: South Carolina Status: Offline Points: 387 |
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Alan,
What diameter is the outlet on the HM manifolds (measured at the flange where the riser attaches)? Thanks, Matt |
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JoeinNY
Grand Poobah Joined: October-19-2005 Location: United States Status: Offline Points: 5693 |
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Well it's 2009 and time for everyone to get back to working on solutions to worlds most pressing issues like the massive deficit of 60 mph correctcrafts, so we better get this thread back on the first page. I took the opportunity to measure the exhaust ports on a couple manifolds over the holidays and thought I would share the results for reference. On the hiteks the opening is approx 1.29 inchs x 1.53 inches high the runners are big and smooth but have some dimpleing for the bolt heads. On my pcm manifolds that are ported as far as I would consider safe the openings are more peanut shaped. The port ended up about 1.45 high and near the top and bottoms 1.28 wide, however near the mounting holes they neck down to about 1.18. The runners are fairly smooth but restrict down quite a bit after the interface due to mounting bolt head dimples.
Alan, How big are the ports on the Rhs heads? |
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eric lavine
Grand Poobah Joined: August-13-2006 Location: United States Status: Offline Points: 13413 |
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I think some work could be done to get some good clean fresh air in the engine boxes, it gets pretty hot in there and air is pretty restricted and i personally dont think the engines breath enough...thats me though, dollar for dollar it is cheap to get more air in the compartment
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"the things you own will start to own you"
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JoeinNY
Grand Poobah Joined: October-19-2005 Location: United States Status: Offline Points: 5693 |
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While that might be an issue in some of these boats, particularly older examples it is not an issue in my 83, I have run it down the lake with no motor box and saw no significant change in performance, just louder and scarier. |
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5768 |
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Thanks for bumping it Joe, I thought everyone lost interest!!!
I'll get the port dimensions on sunday and post them. I'm almost ready to start pulling the 81 apart, I've been waiting for all my parts to come in before touching it. I should have the HM manifolds back next week, they needed some machining and since it's being done as a favor I've had to be patient waiting for them. I'm not sure if I'll ever get to the flow testing as work has taken a few turns and I'm going to be fairly busy the next few months. I would still like to but's it not a priority right now. |
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You can’t change the wind but you can adjust your sails
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eric lavine
Grand Poobah Joined: August-13-2006 Location: United States Status: Offline Points: 13413 |
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Joe, I think as you are running, the wind over the windshield creates a vacuum, so i dont think it would help with the cover up or down.
I was more on the lines thinking of forced fresh air from the front of the boat...it just seems the little venting they have now doesnt matter |
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"the things you own will start to own you"
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5768 |
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Joe, The RHS exhaust ports are square at 1.34x1.34 Again I hope to have the manifolds back by the weekend so I'll measure the HM before and after porting.
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You can’t change the wind but you can adjust your sails
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M3Fan
Grand Poobah Joined: October-22-2005 Location: United States Status: Offline Points: 3185 |
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What's the logic in using the HM manifolds? Are they proven to flow better?
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2000 SN GT40 w/99 Graphics/Gel
2016 SN 200 OB 5.3L DI https://forum.fifteenoff.com |
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