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Ralph Savarese
04-21-2002, 07:54 PM
What do you guys think is a ideal rpm to run wot sb Chevy.
JP BRESCIA
04-21-2002, 08:02 PM
Are you running a stock merc?
HP 600SC
04-21-2002, 08:24 PM
Too general of a question without knowing the
details of the internals.
Ralph Savarese
04-21-2002, 08:34 PM
Volvo 270 sb Chevy Crane cam 272 edelbrock performer Rpm Qjet 4" exhaust Right now i am running a 14 1/2 22.5 with a cup 5100 rpm me and a full tank. I was thinking re pitch to 24 should get me to about 4800 does 5100 sound too high?
HP 600SC
04-21-2002, 08:46 PM
what size valves and is it a 4-bolt main?
Sam
04-21-2002, 09:02 PM
Stock motor 48-4900 non stock 5200, just my thoughts based on going from stock to non stock. I run my SBC @ 4900-5000 WOT. Keep in mind that the motor is not the only thing you should be concerened about, don't forget the drive. Alpha's will not hold up as well as the Bravo's at high RPM. No matter what drive you have I would put a drive shower on it.

Sam
Rootsy
04-21-2002, 09:09 PM
don't you really want to prop the boat to run WOT where the camshaft produces peak power or just before it? although there are certain limitations on what a non race prepped motor will handle as well as a sterndrive...

i run a comp cams valvetrain with the camshaft making peak HP @ 5000 rpm... so i target 4800 - 5000. i don't care to exceed 5000 rpm with my motor either...

darn it sam you stole the words right out of my mouth! :p
GEOO
04-21-2002, 09:27 PM
6800-7000 wink

Joke.... What do the cam specs recommend? What type of spring do you run? Guess would be 5000-5200. GEOO
Ralph Savarese
04-21-2002, 09:33 PM
stock springs cam said 2000 - 5000
GEOO
04-21-2002, 09:56 PM
Ralph,

If your springs are rated for 5000 then don't go over that... If you under or over rev 100 rpm's it's no big difference with speed. A little higher pitch will give you a better cruise speed.
Rootsy
04-21-2002, 10:12 PM
you run stock springs with an aftermarket camshaft? do your stock springs have the required seat and open pressures to match the requirements of the camshaft? apparently they have enough clearance to not run into a spring bind situation... most stock springs are pretty wimpy and running them with a hi-perf camshaft can drastically shorten their lives, especially at high rpms... too much ramp acceleration without enough spring rate can lead to valves bouncing on the seats, lifters lofting off the nose and nasty things of that sort...