Depends on the engine :-) Late model 1 ton truck block, 4 bolt main, chevy
pink rods, keith black pistons, crane roller cam and roller rockers,
edlebrock performer rpm aluminum heads and aluminum intake.

"Tony Thomas" wrote in message
news:muhQc.90170$eM2.58740@attbi_s51...
Don't know what boat you have James but Turning a 5.7 at 5200 rpms for 4
or
5 minutes at a time will destroy the engine. Don't expect it to last more
than a couple of seasons if that long.

--
Tony
my boats at http://t.thomas.home.mchsi.com

"JamesgangNC" wrote in message
k.net...
That must be a pretty heavy boat. Try going back to the 17. You might
even
want to try a 15. Personally I prefer to run the wot rpm a little high
to
improve the hole shot. After all you can control how long you run it
wide
open. I let my 5.7 turn about 5200 but seldom keep it there for more
that
4
or 5 minutes.

"Joseph Stachyra" wrote in message
...
I keep telling people, 4 blade props will slow you down, and nobody
listens.....
go back to a 17" three blade, or check with a boat dealer what the
original
prop was....
if you want to push a 4 blade, then go to a 250 hp outboard.

"Shawn Willden" wrote in message
...
I have a 20' Bayliner, a 1990 with a 5.0L Merc and (I think) Alpha 1
outdrive. The engine has been modified with a 4BBL carb (now a
marine
one,
for those who followed my earlier travails!) which should give it
about
230
HP (as comared with 200HP with the original 2BBL).

After getting the engine fixed up with the right kind of carb, I
took
it
out
on the lake last week and while the engine seems to run well,
there's
absolutely no way the boat could have gotten an adult out of the
water
on
skis. Top speed is pretty good (nearly 40 mph, and this is at an
elevation
of over 5000 feet) but the boat is really slow to dig its way up
onto
plane. As you might guess from the subject line, I suspect the
prop.

This boat apparently came with, and was pretty much always run with,
a
three-bladed 17 pitch prop. This spring, however, the former owner
trashed
the prop on a sand bar. Before he sold it, he purchased a new
four-bladed,
19 pitch aluminum prop (don't know what the diameter is, but it
looks
about
the same as the previous 17-pitch prop, which he left in the boat).
My
suspicion is that this prop is just too much for my engine to turn,
but
I
don't really know if 2 inches of pitch make that much difference.

At plane, with a wide-open throttle (assuming the throttle cable is
adjusted
correctly), the engine peaks out at 3500 rpm. According to a
Mercruiser
manual I have, it should run to about 4200 WOT.

So, before I go buy a prop, what do you all think? Should this
engine
be
able to handle a 19 pitch? Actually, I'll buy a prop anyway,
because
it's
cheaper than looking into deeper engine problems, and if it gets me
acceptable performance, I'll stick with it. However, if the current
performance indicates that there might be other problems, I'd rather
know
sooner rather than later, even if I decide not to do anything.

Thanks for any help,

Shawn