Camshaft Selection

[ck7684]

I have a question about camshafts...can anyone recommend some specs? I have an 454 with a Berkeley J12F and "A" impeller. My main issue is that I want to stick with the stock "wet log" style exhaust manifolds.
The boat is a '79 16' Cobrajet. I'd also like any info about this boat if anyone has any...
Thanks!!

[FOURQ]

I have a question about camshafts...can anyone recommend some specs? I have an 454 with a Berkeley J12F and "A" impeller. My main issue is that I want to stick with the stock "wet log" style exhaust manifolds.
The boat is a '79 16' Cobrajet. I'd also like any info about this boat if anyone has any...
Thanks!!
pm cstraub69 on the boards he can set you up with the perfect cam

[SmokinLowriderSS]

Something like mine would be a good fit.
You're going to be maxed arround 350HP with the logs, maybe a tad more. I'm running an Isky Custom grind hydraulic with very aggressive ramp rates, and I love it. Got it from Hi-Tech and it has behaved exactly as advertized. Perfect for my working lake boat I wanted to muscle up without going excessively radical and causing myself more work/less enjoyment.
.565" lift, 280* seat duration, (I think the .050" dur is about 232*), and like I said, non-standard ramp grind rates.
With logs It pulled right arround 350HP, 4800 RPM to a well-fed Berk "A" impeller, with thru-transom Lightning headers, an Agressor "B" (same cut as berk "A"), 5,000 RPM (400HP), and that is all at the very stock 8.5:1 (maybe less) comp. ratio, Edelbrock Performer RPM Air Gap manifold, single Holley 700 CFM carb, and bone stock large oval port heads.

[ck7684]

Thanks for the info. I am basically hoping to retain stock power. The stock engine is an Indmar 454 with rect port heads. I have a set of oval port Edelbrocks I'd like to use also. This boat runs 70 mph (GPS) at about 5000-5200 rpm. Does that sound about right? I really dont have room for headers if I want to keep my engine cover.
Thanks for the help...

[ck7684]

...or does anybody know what Indmar was using for cams in these engines?

[SmokinLowriderSS]

Indmar in MY 1978 engine used the factory GM "High-Lift Hydraulic" cam;
.461"/.480" lifts
268*/274* durations
Those are Int/Ex specs.

[ck7684]

Thanks. The Indmar tech guy just told me he didnt know, but that it would have been the "standard" marine cam. Do you know what those duration specs are taken from?
What was the boat this was in?? Basically I just dont want to lose any performance when I rebuild this engine...

[ck7684]

Oh yea...you dont happen to have a part number do you?? Or lobe separation?? Current GM marine cams are 115* but a lot of aftermarket (comp) seem to be about 112*...will that cause any problems?