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-   -   What is the safe RPM range for a 434 Chevy engine (https://www.racingjunk.com/forums/showthread.php?t=34661)

VJ535981 01-12-2015 08:59 PM

What is the safe RPM range for a 434 Chevy engine
 
Need to know how much to turn a high compression 434 chevy engine.
I've been shifting at 6500 RPM and everything seems to be working great. I know there is more horsepower in turning more RPMS however since the engine is a stroker with long stroke I'm thinking maybe it would be better to shift at lower RPM's and let the torque from the engine work.
I'm using a turbo 350 transmission without a transbrake to compete in the no electronics class.

curtisreed 01-13-2015 03:53 AM

There is now way anyone could give you a decent answer to your question with no knowledge of your heads, cam timing, carb size, compression, etc..... That said a big small block like that has to have some really good heads to turn a lot of rpm. You're talking big block cubic inch in a small block platform. Heads on these engines will go into choke pretty early compared to a 350ci engine.

With that said, I would hope that it wouldn't peak under 6800 or so. Basically try raising your shift and see what it says on the time slip. Also, I don't know what rpm you are leaving at on the brake, but I have found that many times leaving at too high of an rpm like a SG car will slow you down. My car is quicker leaving at 3800 than it is leaving at 5500. It gets a run at the converter and uses the torque multiplication better in the early part of the run. Hope some of this helps a little.

Curtis

TheRabbit 01-14-2015 03:09 PM

Being a 434 I would ASSUME it's a very well built motor. IF that's the case I'd run it to 7,200 then 7,400 then 7,600, etc and see what the time slip says. Well built small blocks usually have no problem turning 7,000 +.

oldandtired 07-18-2015 07:48 AM


Originally Posted by curtisreed (Post 270249)
Also, I don't know what rpm you are leaving at on the brake, but I have found that many times leaving at too high of an rpm like a SG car will slow you down. My car is quicker leaving at 3800 than it is leaving at 5500. It gets a run at the converter and uses the torque multiplication better in the early part of the run. Hope some of this helps a little.

Curtis

Curtis,
How much time did you remove from your box to make up for the converter's ramp up time?

jmarksdragster 07-18-2015 11:56 AM

I've spun my 4.25 stroke 461 SBC to 7900 regularly. Just depends on the parts you used.

curtisreed 07-20-2015 03:55 AM


Originally Posted by oldandtired (Post 270889)
Curtis,
How much time did you remove from your box to make up for the converter's ramp up time?

Dave, I don't box race. I was index racing on a pro tree.

Curtis


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