BBC Rotating Assembly Question

[ItDoRun]

Are BBC rotating assemblies internally or externally balanced? I've always been told they are balanced at the flywheel, but I see the Eagle assemblies on Ebay that are internally balanced. Can anyone educate me on this?

Thanks,
Chris

[camcojb]

The 454's are externally balanced with a specific balancer and flywheel for the stock engine. The 396/427's are internally balanced. But many of the aftermarket rotating assemblies can be internally balanced, so if you have a stock 454 you'd need to swap the balancer and flywheel if you go internal balance.

Jody

[ItDoRun]

My plans are to build a 489 stroker. What type of balancer and flywheel would I need?

[MarkM66]

1st, don't buy engine parts off of ebay. I'd recomend buying from your local machine shop. That way if somethings not right, they'll have to stand behind it. And you won't have to be shipping parts all over. They can also advise you on the right parts to get.

Jody's right, some are internally balanced, some external. Find that out before you buy your kit so you can get the matching damper and flywheel.

[Lowend]

Its ALWAYS better to have an internally balanced setup.
What you are probably looking at is buying a crank made with internal balance in mind, the rods are the same in either application.
A machine shop will have to do the actual balancing, and will likley have to weld a piece of mallory metal to the crank to get it done. Not a big deal, maybe an extra $300 over a conventional balance job.
The harmonic Balancer will be one for a 396 or 427. I have had good luck with the SFI rated Professional Products models