Visit The Dirt Forum for More Information

Author Topic:   400 sbc rpms?
Dirt Freak

Total posts: 285
posted July 10, 2002 11:06 PM UIN: 40696038
what is the most rpms you should run in a 400 small block chevy?

Dirt Full Roller

Total posts: 73
posted July 11, 2002 12:48 AM
One of our motors in our modified we spin 7600rpm with no problems. But we did put 5.7 rods in it due to the face that people say that the stock 400 rods are kind of the weak point of the 400

Dirt Freak

Total posts: 353
posted July 11, 2002 08:21 AM
I agree with dodgeboy. If you build it right you can run them pretty hard. Make sure you have a good bottom end just like any motor.

Dirt Roller

Total posts: 23
posted July 11, 2002 10:25 PM
just rember to build it light and twist it tight

Dirt Forum Racer

Total posts: 96
posted July 13, 2002 10:16 AM
It sounds like Dodgeboy Put some extra money in his bottom end. Not that theres anything wrong with that, But I have never turned my 400 sbc or my 406sbc 7600rpm. Not to say its not possible if your willing to spend a little extra cash. We run a 3/8 slightly banked "D" shaped track, My 406 on Alky on a dry slick night we usually turn max 7000rpm. But you dont need the higher RPM because the 400 with the right cam have tons of low end torque and pull hard without turning the high RPM. But thats just my personal opinion.

Dirt Full Roller

Total posts: 73
posted July 13, 2002 09:51 PM
nope, just a stock cast crank, 2bolt mains, and a set of eagle rods. thats it. But keep in mind our motors are run in an IMCA modified, so there is not a lot of tire to deal with dragging the motor down

[This message has been edited by DodgeBoy76 (edited July 13, 2002).]

Dirt Full Roller

Total posts: 31
posted July 16, 2002 03:00 AM
What is the advantage of running a lot of R's? One of the guys in our club turns his motor 9600 RPM's. He has a high dollar aluminum motor (430) and he usually runs up front. We are in the process of building a 406 steel motor with Brodix heads. We plan to put it on the dyno and let the numbers tell us how fast to turn it. I think our engine builder said it should be about 7000.

Dirt Maniac

Total posts: 119
posted August 10, 2002 06:23 PM
I have a 408 and i turn it 7500 rpm and no problems out of it. Just like someone said in the post above if it's built right it'll turn nice high rpms. I run 6" rods and a lunati crank. Just make sure your bottom end is good. I got about 2K in my bottom end.

Dirt Roller

Total posts: 14
posted August 12, 2002 09:55 AM
I changed from a 355 ci with 6.20 gears to a 406 with 6.20 gears and went slower lap times. I changed the gear to a 600 and picked up a little. I changed to a 5.88 and became real competitive. Could have been the cam combo but My 406 was a lot stronger if i pulled off the corner at around 4500 and turned about 62 or 63 at the end.

Back to the Archives