building 502 ?
 

building 502 741 cam large oval port heads some bowl work done and edelbrock air gap performer rpm is this a good set up or should i use rec port heads and single plane intake boat is heavy

Re: building 502 ?
 

imsurprised you havent seen a follow up...hang tight. it sounds like an ok set up to mebut im new to this stuff, what heads, what exhaust are you looking for just more HP/top speed? all these gurus will want to know this and more........
do some forum searches if you havent already......good info there!!!

Re: building 502 ?
 

I'm curious to know if they are Merlin oval port heads? I'd say yes, on the oval port heads and the Air-Gap intake manifold. Many would probably not agree with me, but the specs of the Crane 741 cam wouldn't necessarily be my first choice---I think it's a little too large for your application. That's only my opinion, but it is not set in stone.

A friend of mine built a 509" marine engine with some 308cc Merlin heads with NO PORT work, 8.8 comp ratio, Air-Gap intake, Holley 950 carb, and a 741 cam and it made 563hp @ about 5800rpm or so. Torque peak was right around 620 foot lbs from 3600rpm. I remember the torque curve being very flat. Dyno tests were conducted on Tyler Crocket's dyno. The engine was installed in a 27' Warlock. I remember the excelleration was very quick---it ran very well.

I would seek the advice of someone like ''rmbuilder" (Bob) for a better, and more accurate cam selection. He is very knowledgable with that kind of stuff, but so far I'd say you'd at least be in the ball park with the components you have listed in your first post for a heavy boat. Have fun!

Re: building 502 ?
 

What about the 731? Seems close but more "heavy" friendly. But jees 620ft/#s will push a lot of heavy too!

Re: building 502 ?
 

Why buy an "off the shelf" cam when you can have one tailor made to your application.
I also endorse Marine Kinetics (aka. Rmbuilder of OSO) for a marine specific ground camshaft and related valvetrain components.

Re: building 502 ?
 

I'm working with RMBuilder as well.

Not sure if you actually bought heads yet but I'm selling a set of GM 088 Rectangular port heads with a some port work. They have inconnel valves and could probably use new guides and a valve job. Let me know if interested. They made 550 hp on my 509s.

Re: building 502 ?
 

I have a decent set of heads if you would like ot look at them.