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Author Topic:   Max RPM
posted October 22, 2003 07:22 PM           
Here's what I'm running at...
1/2 mile highly banked (22 degrees) asphalt track... San Antonio Speedway
My engine will be a 350 bored to 355 with 5.7 rods (rules). I need to run a 50 pound crank (stock). Heads must be non-ported stock heads, with valve job, 2.02 1.6 valves (or something like that). I can run high performance heads (lightweight); they will be flat top with valve reliefs. Running 104 octane race gas. Two barrel holly 350cfm carb. I can run any cam but they have rules on max lift and stuff.

Ok.. now my question. Assuming my engine is put together right (by me or by a professional), what max RPM should I shoot for? Once I know my RPM range I can pick a cam and rearend gears....

So, what kind of RPM should I expect a motor like this to see if I want it to last all season?


dan ferry
posted October 22, 2003 07:50 PM
do you have to run stock intake and exhaust manifolds. what kind of rods and crank? what do rules state on cam lift ,vacuum,?f u dont want to sink alot in bottom end id say 6000rpm. what rear end u using

posted October 22, 2003 08:37 PM           
edelbrock 2102 intake, headers allowed... i think the cam lift max is like .500

What would a "good" bottom end give me for RPM?

posted October 22, 2003 08:52 PM
It isn't so much your bottom end that'll be the limitation to your rpms as it is that 350cfm carb.
Most classes that run that carb are seeing most racers stay under 6500rpm at the most, but then again, it depends on a LOT of other things, not the least of which is whether or not there are strict limitations on what can be done to the carb, as well as compression limits and/or angle milling rules on the heads.
A good balanced bottom end, good rod bolts, and rods, and a properly assembled bottom end with all good parts and you'll do fine up to 6500rpm at least.
The trick with those little carbs isn't to be concerned with max rpm, it's putting the torque curve where you need it for the track in question. And the only way to know that is to know what everyone else at that level typically has for an rpm range.
My guess, being it's a pavement track, is that you're going to reach for 6400 or so rpm, and come off the corners around 4500 or so. But that's just a guess...

Hope that helps,

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