Finish my 509
#11
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Small Canfields are the best heads for your type build imho. Unported,I think the ovals would cost you a few horses up around 5000. Build a good valve train. Doyou have room in the budget for roller rockers? With al. heads and a cam that big , you could probably get away with a little more compression. A small dome about 10 cc would be good. 0 deck the block and you would be just under 10 to 1. The engine would run better but it would require better gas.
Last edited by PatriYacht; 01-12-2007 at 11:23 AM.
#12
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I'm seriously considering selling the flat top pistons i have and buying the small dome profile SRP to get me near 10:1. Seems to be more 118cc heads out there for sale than the 108 or 110cc heads i will be looking for. Dunno, we'll see. Does anyone have experience with the ProComp marine billet distributors with MSD caps that are on ebay for about $175? I know it is chinese stuff but it sure is a lot cheaper than the $325 MSD one. Thanks, Dave
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Be careful with high comp ratios for marine applications. With the way fuel quality is these days, I would try to keep comp ratio down....the quality of fuel seems to be becoming more and more questionable as time goes on. It's no fun trying to find special octane fuels for your boat especially right when you need it-----AND that's especially true of a marina! Or expect to carry lots of TORCO fuel octane boost additive with you.
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Hey Dave,
You might want to find bobl on here he is usually in the Nordic forums. He owns Full Throttle Marine in Austin Texas. You could pic his ear, he could give you some good ideas.
You might want to find bobl on here he is usually in the Nordic forums. He owns Full Throttle Marine in Austin Texas. You could pic his ear, he could give you some good ideas.
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I don't think you'll have too much compresion with the 110cc chambers. And I also think that you can make 600 flywheel HP with a decent cam (such as the one you have now) if you get the right heads and manifold to go with that cam.
My Teague/Merlin Marine 509 came with small-dome pistons (14cc) and a cam w/ 226 deg. int. & 234 deg. exh. duration and .587" int. and .610" exh. lift w/ 112 deg LSA.
With the Merlin VR 345 cc cast irons heads w/ 119cc chambers (these flow relatively poor IMO) this motor came from Bill Mitchell with a dyno sheet which showed it made 574 hp @ 5600 rpm and 631 ft.lbs of torque @ like 4800rpm. This was with the Merlin Marine single plane intake (which has slighly larger ports (exits) than the Dart manifold (but the Dart might actually outperform it).
For the best power I would suggest that you use the Dart 335cc CNC Pro-1 or AFR 315cc CNC heads and the Dart manifold. I think your engine would make over 600 HP with these provided you can get the heads machined to like a 114cc chamber and use the thinnest good quality gasket you can find (probably like .038").
A cheaper option is the Edelbrock Marine heads which come with Inconel valves but without springs and retainers.
These are available hard anodized coated in either an oval port with the 110cc chamber or rectangular port with a 118cc chamber. The oval will give you more compression but less power with your combo in my view.
If you don't have to have aluminum heads, give Valako Racing Heads a call and ask Jim Valako what it would cost you to port a set of Dart Iron Eagles and you might find that these would give you the most "bang" for the buck. In fact, just call Jim first and I'm certain he'll give you an honest opinion and damn good advice. And he can make any head flow better. I just had a set of AFR's done by him and I have no problem reccomending his work to anybody.
Just my 2 cents...
My Teague/Merlin Marine 509 came with small-dome pistons (14cc) and a cam w/ 226 deg. int. & 234 deg. exh. duration and .587" int. and .610" exh. lift w/ 112 deg LSA.
With the Merlin VR 345 cc cast irons heads w/ 119cc chambers (these flow relatively poor IMO) this motor came from Bill Mitchell with a dyno sheet which showed it made 574 hp @ 5600 rpm and 631 ft.lbs of torque @ like 4800rpm. This was with the Merlin Marine single plane intake (which has slighly larger ports (exits) than the Dart manifold (but the Dart might actually outperform it).
For the best power I would suggest that you use the Dart 335cc CNC Pro-1 or AFR 315cc CNC heads and the Dart manifold. I think your engine would make over 600 HP with these provided you can get the heads machined to like a 114cc chamber and use the thinnest good quality gasket you can find (probably like .038").
A cheaper option is the Edelbrock Marine heads which come with Inconel valves but without springs and retainers.
These are available hard anodized coated in either an oval port with the 110cc chamber or rectangular port with a 118cc chamber. The oval will give you more compression but less power with your combo in my view.
If you don't have to have aluminum heads, give Valako Racing Heads a call and ask Jim Valako what it would cost you to port a set of Dart Iron Eagles and you might find that these would give you the most "bang" for the buck. In fact, just call Jim first and I'm certain he'll give you an honest opinion and damn good advice. And he can make any head flow better. I just had a set of AFR's done by him and I have no problem reccomending his work to anybody.
Just my 2 cents...