Chevy Flywheel Swappin'

[79D604SPD]

Want to replace my worn-out 400SB with 4-speed trans on my 1979 K20 to a 402BB. But my flywheels won't interchange obviously because the 400SB is externally balanced. I have a flywheel from a 1970 250 inline six chevy truck. I might be able to use it because, when I was browsing a junkyard website, according to it, a flywheel for a 402BB is the same as a 350ci, 305ci, and a 250ci as long as the clutch disc size is the same. Is this true?

So 396ci,402ci, and all internally balanced small blocks can use the same flywheel or not?

And with a 400SB and 454BB being externally balanced, do they use the same flywheel?

Thanks for any help.



:cool:

[max75432]

I installed a 400 crank into my 350 4 bolt engine. To make it work right I had to use a 400 fly wheel and harmonic ballancer.

The chevrolet house said the 454 and the 400 used diffenenmt flywheels and are ballanced different. Check out the numbers
on the parts at the chevy house and they can tell you what engine it came off of.

The 350 heads are a heavier built head and will work right on the 400 engine. But you will have a machine shop drill steam holes in the heads for the 400.

I hope this will help

[79D604SPD]

Thanks for your help, I knew that about the 350 and 400ci heads. I have seen a few people use 400 heads on 350s with no problems, and I knew 350 heads had to be drilled to bolt onto a 400. I will check and cross some numbers to see if my internally balanced 250ci flywheel will work on an interally balanced 402ci. If it will, I will have it machined and install it. thanks

[79D604SPD]

According to LMC truck's catalogs, the flywheel part number is the same for a 250 6 cyl, 283, 305, 307, 327, 350 V8 small blocks, and 396, 402 Big Blocks. This is for future reference for anyone who wondered the same thing I did.