On Sat, 03 Nov 2007 10:57:15 -0700, crisslenhart@sbcglobal.net wrote:
I have a 32' Luhrs Sportfisher. Currently with Chrysler 318 engines.
I have 2 Chevrolet 350 4 bolt marine engines, one standard, one
reverse rotation. I would like to find out what spec. and what parts
I need to build these engines to 280 to 300 hp on carburators. The
boat weights 17000 lbs. It is my understanding I need foot lbs. of
torque more than rpm. Anyone know if there is a guide or book? Anyone
with information. Thanks in advance.
The most I've seen from a carburated 350 is 260 hp. You can get 300 to 320 with multi-port fuel injection, maybe more. With 17,000 lbs of weight you'll be a lot better off with 454s or even bigger. My old Bertram 33 weighed 21,000 and it was only a marginal performer with 350 hp 454s.
Who's marine chevys are they? Are they late model with roller lifters? Can't tell you what's in them with out knowing which ones they are. Gm makes them all but there are a number of variations depending on what year they are and who they were being sold to.
When you say "build" do you mean hop up or do you mean complete rebuild? Cause a long block core is only worth a couple hundred bucks so I would consider other choices. Big blocks or a diesels would be a better fit.
The factory small block marine cam is a decent cam. Not sure you could do much better. Add an aluminum manifold and a holley 700 and you might get it near your 280hp. You could bump up the compression a tad but not much given today's octane. Also if you underprop it a bit that might help. Hard to get a lot of torque out of small block anything.
Here's my mouse motor but I'm probably only getting 280 or so hp out of it. I started with a 4 bolt truck core. Aftermarket pistons, pink rods, edlebrock intake and heads, holley, crane roller rockers, stainless exhaust. It has the factory marine roller cam but the rockers are 1.6 instead of 1.5. I had a aftermarket cam but it cost me low end. Went back to the factory cam.
Are the 318's the old "Big Blocks"? if so, they are vertually the
same blocks as the the 383's, 413,s qand 440's, which would be easier
to overhaul and get the horsepower/torque you're looking for.
The MoPar 318 came in a big block version?
Never knew that.
Eisboch
Yes, Richard.
As a matter of fact, they did. There was the 60's 318 "A" block, up
intill I think about 1967 or '68, then chrylser happened to come out
with the 318 "LA" in a small block version. Wich was essentially in
the family of the 273(?) 340, 360
That;s like in the 60's, Pontiac had a 326 and the 389, and 428 had
the same block same block
Um - again, I'm not up on MOPAR stuff so I looked around a little and it confirmed what I do know. The "A" block that produced the 318 was the late '50s 303 block which, if I remember correctly, was small block.
Tom, Richard and everybody else. I DO STAND CORRECTED! The early 318
"A" was NOT clasified as a "Big Block" but rather a Polysphere (or
Wideblock) 318. Obviously not the same as the 318 "LA" which was
classed as a true "small block" but not the large 383-440 Big Block
either, even though it did have heavier castings and big block
"characteristics". But I'm still not sure if the 413 is in between
the 383-440's or if it was an over punched wide block 318.
Again I Humbly apologize.
You learn something everyday.
No reason to apologize - all those different engines of the day were simply amazing.
There aren't very many "classic" engines, but certainly the 318 stands alone as the best engine ever developed. I might rank the 220 slant six as one and the 220 Silver Diamond International six as another.
Also considered - 327, 350 and the great 564 International/Ford truck engine along with the 7.3 liter diesel.
