The 400's have siamesed cylinders so they are not very popular in the marine
world. They have cooling problems right where the cylinders meet which is
also right where head gaskets tend to blow out on small blocks.

The stroked 383 is a pretty good configuration but don't expect miracles.
It is just a slightly longer stroke and 33 more cubic inches.

The basic problem is still that the small blocks really like to make hp with
rpm's and there is a limit to what you can do to get hp at low rpm with
them. It's an unavoidable problem when combined with a big heavy boat.
That's why higher displacement is really the way to go in a big boat.

I think the op is gone anyway.

"Capt John" wrote in message
ups.com...
On Nov 3, 1:27 pm, Wayne.B wrote:
On Sat, 03 Nov 2007 10:57:15 -0700, 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.

I had 350's with carbs and 300 hp, it's not difficult. A better choice
is to make those 350's into 383's, plenty of torque at low RPM's and
still light weight. Even better, if you can find them, small block
400's. But to do any of this you need a good engine shop that knows
marine engines. Their's so many choices of heads, valve sizes, cam
shafts.

About five years ago I had a shop I've been dealing with for years
build me 300 hp 350's, completely remachined, new sheet metal, pistons
rings cams, bearings timing gears and chain, oil pumps, ect. Bottom
line, $2500 each, I'd probably bet their about $3000 each now. The
best thing about 350's are the parts are cheap!!!