auto to 4speed does the motor need rebalanced

[denn468]

i have a 468 bbc external balance automatic going to muncie 4 speed does the motor need to be rebalanced or the fly wheel only or nothing at all thanks

[BEAST477]

You just need an external balanced flywheel.

[denn468]

i understand but the motor was balanced with the flex plate and the fly wheel counterweight would be different right maybe im missing something here thanks

[zipper06]

That's a real good question, i think the counterweight would be the same but that's a lot more weight hanging off the end of the crank, kinda like putting a crank hub on VS an 8"00 balancer. Might not be an issue unless you're running some pretty high RPM. I personally think i would rebalance it, but that's just my opinion, because i don't know the answer.

Zip.

[bjuice]

i 2nd what Zip said...i will bet Vince Tosto can enlighten us on this one.

[jmarksdragster]

If the flexplate was a standard 454 flexplate, you should only need a 454 flywheel. A GOOD machine shop will not drill the flexplate when balancing an external balanced engine.

[burgessdg]

Mark's right on the money. A competent shop will not do anything to the flexplate when balancing in order to maintain that standard. Then if you need to replace the flexplate down the road, you can replace it with a standard 454 flexplate without worry of affecting the balance. A flywheel for a 454 has that same amount of weight in the exact same place on the flywheel as it is on the flexplate. From a balance standpoint it does not matter how much weight you add as long as the weight you add is weighted correctly. What I would do is compare your flexplate to a stock 454 flexplate (that you know has not been modified). If they are the same, you can go with a standard 454 flywheel. You can also go with a 350 flywheel (less mass) by adding a balance weight.
See this link http://www.speedwaymotors.com/p/3262,40_SandB-and-454-BandB-Chevy-Balancing-Plate.html

Good luck, Dan

[kbartley]

Are you planning on going to an aluminum flywheel w/ you're muncie? Kris