New intake manifold choices

Hi everyone, I am amazed how long it took me to register here.

I have owned my 78 351W martinique since 2002, and at that time I did a full interior redo, including stringer repair, and re flooring.

Now I have a minor running issue, and the only thing I can see the problem could be is a bad intake manifold gasket. my boat has a rebuilt Holley 4160 600cfm carb, the stock 4v intake and heads, was running a pertronix for 5 years, but that failed and now I am running a new points setup for the final weeks of the season.

well, since the gaskets are cheap, I might as well throw an aftermarket intake on it.

so, it looks like the non EGR edelbrock performer would be a nice addition. What about the performance products unit? or any other unit? I would rather not have to get a new flame arrestor.

I def do not want the RPM versions, since I want the low end power.

also, will I have any clearance issues with the performer? I have the stock flame arrestor, which is ~3" tall and ~6" in diameter.

Do I have to use marine intake gaskets? or are those the same as the automotive ones?

and will i need to modify the throttle bracket?

I am certain I will need to mod my fuel line from the mech fuel pump.


I read about the edelbrock manifold having a plug on it to run the PCV line to it, to maybe get the performer to clear the clamshell. Does that work?
anything else?

I will need a converter plate to run the edelbrock intake with the holley carb, but will the performance products, or weiand, or any other brands allow me to not put another plate between the carb and the intake to allow it to fit under the engine cover???


TIA,

Tom

I would love to do this this weekend so i can at least get some skiing in this weekend.


I know I can get the edelbrock at any auto parts store, as well as the carb conversion, and would there be any additional parts I would need beside the gaskets , some RTV, and the carb conv kit?

Some like the Wieand over the Performer, but I think it is one inch taller than the Performer. The carb conversion plate is very thin and really shouldn't hamper your clearance. Put some clay, playdo, or silly putty on the highest point of your arrestor, close the lid. Lift the lid and measure the thickness of the putty. I'm running the Performer with gt40p heads and am very happy. Probably be the cheapest route anyway.

I don't have a CC boat. '88 Brendella. I did use a low profile arrestor, but I have no idea of your clearance issues. Use the putty like said to check. I believ that intake is a replica of the performer, but for the price, I would go with the Edelbrock. I used a spacer plate with my carb. And yes, marine gaskets.

Chris, I will give ya 20.00 and you pay the postage, that my best offer..........boat dr

Just for reference, here are (from left to right) the Edelbrock Performer, Weiand Stealth and stock intake manifolds.



We've had this discussion before, so a search would help. The Performer is ~1.5" taller than stock, the Stealth is ~1" taller than the Performer. Use the clay trick to see what kind of clearance you have. Though not easy to find, there are some low profile arrestors out there if you decide to go with a taller setup.

All my research indicated that the taller manifolds (Stealth, Performer RPM) outperformed the standard performer in the midrange- which is where we want the power in our boats. If you have the height, I say go with one of those. You wont lose any low end with those choices. The Performer will still be a good improvement over stock if you go that route.

You may or may not run the risk of leaning out a cylinder by ditching the spacer and running the PCV to the intake runner. I didnt want to take the chance and kept the spacer.

very nice looking motor Tim, gotta love the work you did on the exhaust system

Bigcity wrote: Just looking for comments and advice. I am going to put a little punch in my 1994 351 carbed motor this spring. I have ordered the gt40p heads and will also be replacing the intake, was going to go with Edelbrock performer #2181 but have been hearing comments that the Weiand Stealth is better. For the minimal cost diverence I will go Weiand with low profile arrestor if it will fit under the engine box. Currently boat is in storage so I have ot been able to do the silly putty test. Does anyone know off-hand if this set up will fit.

Assuming you have the 1.23 tranny, it will fit if you can find a 2" flame arrestor. My setup with the Stealth is pictured above.

Are you upgrading the cam at the same time? I highly recommend it.

Yes it is a bolt on , but a Cam would be a upgrade that will only improve the induction package.
Cam Research W/ lifters = cheap horsepower

Bigcity wrote: Tranny is 1.1. The motor only has 250 hours so I was only thinking top end improvements. Compaired to 1999 GT40 Air seemed like engine lacks a bit of power in turns do you know if the performer will fit as an alternative.

Im not positive, but you may run into more clearance issues with the 1.1 due to the engine angle. The 1.23 sits pretty flat. No way to be sure until you do the clay test.

If you can only run the Performer, definitely get the adapter plate- you dont want to deal with vacuum leaks. Many people here have upgraded their intake run to the Performer manifold, by the way.

The cam is very much part of the top end, and will really pull the head+intake package together. The cost of a custom cam+lifter set from Cam Research is very inexpensive (~$200). Just tell them what components youre using and what you want the motor to do and they'll make a great recommendation.

It will be easiest to install the cam while you have the heads and intake off already, so it makes sense to do this upgrade now if youre going to do it at all. If youre not doing the labor yourself, I have no idea what it will cost.

eric lavine wrote: tr, i see you painted the trans lol

Man, I cant catch a break with you guys! The trans isnt getting fresh paint until it comes out of the boat again- which wont happen until the engine gets rebuilt. I hope that doesnt happen anytime soon!

Thanks for all your imput TR. If the cost is only a couple hundred or so for the cam and lifters I will probably take your advise do it right the first time. I hope to be able to run the stock pistons, carb etc so I will contact Cam Research to see what they suggest.

This is a new boat to me and I have only put 15 hours or so on it. The hole shot is strong and it pulls my 210 pound ass out of the water with out hesitation. The motor seems to top out at approximately 4300-4400 rpm and 43-44 mph, I would like to see say 48-50mph with more grunt in hard turn arounds. I hope the improvements will give me 300+ HP.

All the best, Happy New Year.

Bigcity

Bigcity wrote: I hope to be able to run the stock pistons, carb etc

No problem. The stock pistons are fine to run with the upgrades, and the stock carb is more than adequate as far as CFM goes.

Bigcity wrote: The motor seems to top out at approximately 4300-4400 rpm and 43-44 mph, I would like to see say 48-50mph... I hope the improvements will give me 300+ HP

Sounds like youre getting normal performance out of the stock engine. Adding heads+intake+cam should get you over 300hp pretty easily (probably closer to 320hp, depending on the cam specs), and solid 47-50mph depending on how fast your particular hull is.

Bigcity wrote: more grunt in hard turn arounds

I should have mentioned this before, but the first thing you should be upgrading is the prop. That is the single biggest performance improvement you can make. By all means, upgrade to an Acme 540. It will improve all around performance- holeshot, skiability, and probably top end as well. It will bite harder in turns as well.

Tim: I am sure it was a compliment.
Funny how ya feel like ya know a guy on here...even if you haven't had the pleasure of meeting in person.

I gotta agree as to the pic of the motor (engine?), every time I see it I am impressed.

I am not sure how it all works but...when the guys helped me with my '80, the performer plus GT40p heads and tweaking the points gave me 50mph with a 13x13 OJ Legend. I have an Acme 540 that I have not gotten on yet buy am excited to try.

Without a doubt you came to the right place to ask questions.

john

MM used my Legend for awhile and really liked it...thought it was faster on his '80 so you probably are right. He had an Acme that he won at GL and did not like it. But I think Mark is more about spped than I am. Not sure how much if any skiing he does anymore. But me...I use my boat to ski some too so I can't wait to try the 540. If Alan is using it it must be pretty good.

Happy...Safe...Lucky New Year to ya my friend!

john