johnsc91

Having a 5.7l vortec (2bbl) rebuilt. Picked up a nice CI 4bbl square bore. Planed to put 600 cfm Marine Edelbrock Perf carb on, then read couple of articles recommending double bowl Deamon, etc. Any thoughts.

Also, the Merc plate indicates 250 Hp on 2bbl config (@ prop?). Am wondering if would gain much with cam change (reliability is a must), or if existing Merc cam should be left in. Am told that 4bbl w/ good intake will give approx 300 Hp. Would like 325 to 340 if possible without causing other probs (reliability, killing Alpha drive...).

Would appreciate any thoughts / recommendations.

bobl

I've done quite a few of these engines. I use the Crane 104224 cam, with an airgap intake and the 600 Edelbrock. The Holley/Demon offers better accelleration but not really any top end difference. If you will go ahead and do a bowl blend on the heads and add larger valves you'll get a very strong engine, around 400 HP at about 5200 RPM. This cam is very mild and doesn't idle much different than stock. It's actually the same cam Merc uses in the 6.2.

Bob

GeoZ

I am repowering a magnum. Under 500 hours on boat/engine. Carb, intake, cam and lifters $400. takes it. Lifters are in proper order. All parts are in excellent shape.

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johnsc91

Thx Bob.

Have heard good things abt the gap intake. Any issues using Aluminum on marine applications?

Also rebuilding vortec heads. Any benefit in usine 2.02 valves, etc. Worth the cost, reliability ok, etc