Hot Rod Forum banner

SBC performance marine?

27K views 138 replies 11 participants last post by  BuzzLOL 
#1 ·
Hey everyone,

First I will introduce myself! This is my first time on the forum. I have worked on junk my entire life (developing my hands on skills) and enforced that with a BS in Engineering. I have spent my hobby time working on diesels, and this is the first time I have stepped into the gas world. I need to learn.

This forum is called hot-rodders, and after searching, it looks like a great forum. That being said, I need help with an engine for marine application.

My father has a 350 chevy in his 24' cabin cruiser, long story short after a few years of him complaining about how slow it is, I decided to research. It has a 1973 4 bolt 350 in it. SMOG everything, gutless as hell.

I already HAVE a set of 327 double hump 461 heads that are on a 327 in his garage. They are on a 275hp, 327 with a high rise intake (GM). He got it out of a junk yard in the late 70's and rebuilt it to put it in a C10 he was working on.

I am interested in making this 350 ~300hp, maybe more depending on how everything goes.

For marine application, keep in mind we have unlimited cooling (detention due to heat should be an issue), but we also have a continuous load on the engine. Operation RPM will be ~3800rpm, with a WOT RPM of around 4800-5000.

Should I just pull the heads, cam, and intake off the 275hp 327, or is there something we can do fairly cheap to make this even better?

I don't know how to spec out, and match intake with cam and heads.

Thanks guys!
George
 
See less See more
#138 · (Edited)
Good to hear back from you, thought you were permanently gone since no posts since last May... Glad the MPG doubled as well with the 1990's Vortec heads... if you ended up using the 204/214 cam, that would give a power band of about 1,000 - 5200 RPMs, so would prop for a maximum of about 5100 - 5300 RPMs with the usual load in the boat... propping for too low an RPMs can cause the engine to over heat if the water pump isn't spinning fast enough for the power being produced... of course, fuel consumption/HP will increase rapidly above about a 2200 - 3200 RPMs cruise... but the extra power/speed is there if wanted sometimes... the stock 184/194 heavy truck and 194/202 car/light truck cams HP peak about 3800 and 4200 RPMs in a 350" with the 1970's tech low compression bathtub chamber heads... in a '76 400", torque peaked at 2200 and HP peaked at 3600 with the 194/202 cam (prolly factory installed overly advanced)...
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top