24 ft powered by chev 350

[ssicarman]

Hope someone can help me, car engines <br />I know but not car engines in boats. I have a friend running a 24 foot boat that is at present powered by a chevy 350 two barrel. It is unfortunately falling apart, last year bottom end this year rocker arms. He wants to replace it with another chev 350, easy to get them and apparently cheaper than marine engines. The big question is what kind? A truck engine, more heavy duty or four bolt main car engine. The engine runs 3000 to 3500 RPM cruising. I don'tknow how normal that is in a boat, I know that long term unless it's a real good engine it will be hard on it. I would appreciate any input. If mre info is needed I'll get it if I can. thanks very much.

 

[corm]

Re: 24 ft powered by chev 350

Hi Ssicarman,<br />The Marine engine has a different cam,rocker arm ratio, carborator,rod bearings,main bearings,alternator,and gaskets.<br /><br />...hope this helps...corm

 

[magrain]

Re: 24 ft powered by chev 350

Using an auto or truck engine in a marine application is not a good idea. The pistons camshaft and timing gears are all different in a marine engine. The engine would not have the power needed and the cam timing could cause problems with overheating.

 

[savage]

Re: 24 ft powered by chev 350

I did a conversion 13 years ago with no problems. I had a 228 mercruiser (305 chevy) that froze and cracked over the winter. I replaced it with a 350 chevy truck motor that I rebuilt. I bored the block .030 over, installed BRASS FREEZE PLUGS,cam bearings,rod and main bearings,pistons,double roller timing chain,three angle valve job on the heads, ect... using all standard automotive parts.I purchased a marine cam from a local speed shop and used the factory mercruiser intake/carb,water pump,distributer,and exhaust manifolds. The cylinder heads came off of a 1971 chevy truck and flowed much better than the smog heads that came with the mercruiser. The new engine had much more horse power,I had to increase may prop size two inches in pitch to bring my WOT rpm down to acceptable level. MPH also increased. This motor is still running today(sold to a friend)! Boat was used in fresh water only.One other thing ,had to re-jet carb.Hope this helps.