flywheel question on 400 small block

[Jens Jimmy]

I'm having a small block 400 built to replace my tired 350. Question is.... Will my standard trans flywheel work from 350-to 400. Its going in a 4x4 with 4 spd. 205 . any advise would be much appreciated

[camtoys1]

no you a external balance one

[camtoys1]

the front balancer is different too

[kwmech]

You can use a 454 flywheel and have it balanced for the 400. They'll drill a few holes in it on the heavy side

[burnin oil]

Do a google search on this board. We went into this about a year ago and someone provided a link for a reasonably priced 400 flywheel out of Jegs or Summit. Getting the 454 (or SB flywheel for that matter) will take pulling the motor down so they can spin it. If it isn't spun it is only a guess. The other option is a small weight that bolts to the flywheel crank bolts. It will bring it close enough for a stock or mild application. You basically need to think of this process as balancing a tire. You can throw some weight on there and get it close but there is only one way to get it perfect. The real question is how close does it actually need to be to last a long life. Spinning a low RPM 400 that is in the ball park will be no problem, just don't try it at 7k RPMs.

[Jens Jimmy]

Ha Ha, Thanks Burnin oil, and everyone else for weighing in. My motor will be back from the machine shop this week, I'm ready. I bought a flywheel from Oreilly for 65.00 new. Easy stuff, once I knew what I was looking for.

[JMac11]

A 400 Flywheel for $65? I think they quoted you a 400 flexplate for an automatic