What is the highest RPM for SBC 400
 

I am trying to decide what gear ratio to go with but i dont want to be at max rpm at half track. What is the max rpm that i should think about going so as not to do any damage to the engine?

Depends on how the engine is built and what components you used. Give some specifics.

How tall a tire do you have on the back. 26" / 28"
1/8th or 1/4 mile track

Have you had it dynoed to see what RPM max HP and torgue ocurr? Otherwise it will just be an educated or maybe an undeucated guess. :lol: :lol: :lol: :wink:

Like blittle said, depends on how you build it. I had one in high school with stock 2 bolt bottom. Turned it to 6000 all the time with no problems. Now that I'm older and hopefully wiser I would use splayed caps on a 2-bolt block with the lightest rotating assembly I could afford. 400s are somewhat underrated, build it right and it will throw down solid big block numbers.

Building 2 400s right now, setting for 8K rpm max. But one of them I'm using a 3.625 stroke so it'll prolly still be pulling hard at 8K. Other than stroke, building them the same. Using 208 int, having ported now with a super victor.

the biggest problem with 400s is the weak webbing in the block.
I had my mains splayed and installed a crank girdle.

Short stock 5.585 rod length is bad if you intend to turn any significant RPM over 6500. Puts to much side load on the cylinder walls. Longer rod is better.

I'll be running 6"er rods, will help with detonation. Mine are 2 bold main conversions (4 bolt billet splayed caps)