Camshaft for 350
 

I am in the process of replacing the 350/260 engine in my scorpion 230. The engine I am replacing it with was built by a local machine shop, I was told it would have a conservative 350+ hp.(@ 5000RPM) I was just wondering on your take on it. The engine has 9:1 compression 4 bolt stock bottom, (heads) 2.02/1.60 valves with 3 angle blended bowls unshrouded valves and a 30 deg. backcut on valves, cleaned up runners, gasket matched and pinned studs. Weiend stealth air gap intake ( has roughed up runners for better fuel atomization) gasket matched with 2 inch spacer and a holley 600 spread bore carb with stub stack. The cam specs are 262/272 adv duration, 204/214 @ .050, lift 420/442 and a lobe seperation of 112. Stock omc exhaust (for now) with warmed over and smoothed runners and thru hulls. I am concerned with cam. Is it enough to get me to the 350+ hp mark and with a ls of 112 will this give me probs. with water reversion. A lot of the cams I read about are at 114. Any input would be greatly appreciated. Thanks

IMHO your cam should work pretty good as far as in a boat but as far as making 350 hp with that cam and stock exhaust manifolds I highly doubt your going to be anywhere close to that unless you have some really killer heads, I'm thinking more like 275-280, RM builder might chime in with his wisdom, Smitty

I hope I have more than a 15 hp gain over a stock 260 hp merc with 8.5:1 low rise cast intake and carb with a stock heads (76cc 1.94/1.50 single angle valve job) and a cam of 202/214 dur and 395/404 lift. I have alot of time and money into it. Thanks

Go with the lt4 hot cam from gm, it will wake it up and you can run it with stock exhaust

The camshaft you chose is less powerfull/smaller than the stock marine camshaft.
You will need at least 218/224 degrees of duration @.050 lift to get close to 350 horsepower.
The camshaft used in the 350/350 horsepower 1969 Corvette engine had 224/224 degrees of duration @ .050 lift.
For best performance install a camshaft with 110 degrees of LSA (lobe sep angle).
Dennis Moore

I won't have to worry about water reversion with that cam. I thought I had to stay around a 112 or 114 LSA to avoid this.
Again thanks for all the great info.

I agree, cam is REAL small and I would be surprised if it made 300 hp especially with stock manifolds. In the old days I would have bought a cam from Ultradyne for it with numbers like this (IF exhaust was going to be upgraded but stock heads were kept))
276/286 112 .454/.454 221/230 Biggest cam for stock-style spring. Excellent in 350-400 size engines. Largest cam with power brakes. 1500-6000
I really liked that grind and ran it in motors with mild compression with good luck, that cam with 882 heads ran away from my zz4 350/350 hp crate engine in the same vehicle
Today however I would just call RMBUILDER and buy what he reccomends as he optimizes these set-ups. If your motors already done and ready to go in though I would say just run it and enjoy your boat, it just won't make quite ass much as you were hoping for, Smitty

Thanks for all the info. How do I get a hold of RMBUILDER

Comp Cams makes a small block (and BBC) "Maximum Marine Camshaft".....it is the maximum camshaft reccomended for marine use, Im assuming without risking reversion....you may want to check it out.

He's actually in Rochester, 585-654-8583