jvschlegel

I have a stock 502 425hp engine with holly 650 carb, crane cam ignition, CMI e top headers and dry tail pipes. Looking to put a cam in the engine to gain a bit more out of the headers.

Any recommendations for a cam for this set up? In the future, I will either do some aluminum heads, or supercharge.

Jon

1BIGJIM

I hope thats a typeO and its a Holley 850 carb

Griff

What stock 502 made 425hp???

I agree, needs at least an 800cfm carb.

SB

If a Mark IV or Gen V I would convert it to hydraulic roller. If Gen V or VI I would convert to adjustable valvetrain.

Are your heads stock ? If so, will probably need some machine work and new springs,etc to match more agressive roller.

As stated, a 800-850 carb will be needed.

jvschlegel

Let me double check the carb. I will also look over my paperwork on the engine. Just purchased the boat this season and trying to button up some loose ends with the engine. Will post once I find out the info.

Jon

KAAMA

Jon, one very good resource on marine cam applications is Bob Madara of Marine Kinetics. He's also known as "rmbuilder" here on OSO. Bob is a gentleman, is very professional and has helped many with cam apps on here. He can take all of your engine specs and what you want to do with the engine and pretty much NAIL the cam right on! He has helped many boaters here on OSO.

jvschlegel

Thanks for the info. When doing a search I came across a similar resonse and called the phone number attached to Bob's name. Waiting to hear back from him.

jvschlegel

I got home and see I have a holley HP 4150 carb part number 80558, so it is a 830 CFM carb.

After talking to Bob above, I am going to run my engine as is, and when winter comes, go with one of his cams and AFR heads. either the 305 or 315's. Thanks for the help all, very informative. My next delema will be to up grade the carb I currently have when I go with bigger heads.

Griff

That carb will be plenty any 502ci spinning less than 6000rpms. Its a good carb.