I guess back to the OP's question. We took off the Chevy square-port heads and "massaged" some 049 big ovals. Changed intake to an oval and matched it to the heads. Bigger valves, tons of headwork.

For the cam we called Comp Cams and they actually (at the time) had an "offshore" program. After a few circular calls thought the system, they had some cam grounds develped that they had been working with offshore engine builders to get the most out of a dedicated offshore motor. To be honest, I don't remember the part number or specs offhand, but I remember we laughed because the "part number" was scribed with a vibro-engraver on the front!.

Sounded awesome, made 507hp naturally aspirated at a 107 VE, nearly 500 f/lb from 2500 rpm on, and fell on it's face at 6400rpm. Super powerful, no. Best boat motors I ever had, yes!

Super impressed guys. Keep it up!

Now I have to go and dyno and tune three others this week.

It is refreshing to see this forum has moved away from the monopoly it has been for so long and now there can be a free exchange of information from various other parties.

How about the guy who had a custom specd cam, and gained almost 20hp and lost no torque on a mild 575hp engine by retarding it 4 degrees from its recommended centerline. They really hit the nail on the head on that cam design.

Nothing like some validation when back to back dyno testing combos.

Kevin,
98% of the stuff we do is based on existing lobe profiles. Some of these have been around 30 years or better. The key is to give the engine the right amount of lobe area for the given CID and rpm range. .050" numbers are for marketing cams and don't tell you anything. Being able to see .100, .200, 300 numbers allow you to see what is going on.

We enjoy modern day heads that flow a ton of air quickly. Because of this and relatively low rpm range most boats turn, lift on marine cams don't need to be that large IMO.

I had a buddy suffer from breaking morel lifter tie bars with a marine kinetics camshaft also. I belive it was blamed on morels quality.

Johnson lifters. Any input on them? Supposedly bob did a highly scientific test where the johnson lifters outperformed the morels, hence why he supposedly sells the johnsons now.

that was my goal back in 2000 with the currant engines.Seems to have worked for me for years now. JMHO

I was kinda getting ready to yank the motor and go with a custom cam as I hate the feeling of leaving something on the table, but this thread has been very enlightening. It's not that a custom would do me well, but I'll stick with the ZZ502 unit that I've got until I'm ready for a full tear down.

I have a buddy in a 33' Fountain that won LOTO several years. He had engines from Innovation, Reher-Morrison, Hans and finally started building them himself. He left nothing on the table, except reliability. By half way through the summer he was riding with someone else. I told him if he would just take 100hp out, it would live forever. He said she couldn't think of being "challenged" somewhere and didn't have it all there. It's all POV.

Too bad we didn't have more time to play....