I run an externally balanced 383 using an OEM GM 8" balancer (GM part# 6272225). This is the balancer that was used when the rotating assembly was balanced initially and was always on the engine. I recently read somewhere that these stock balancers aren't suggested for any regular use beyond 4500 rpms. Since my car is used 75% of the time at the track, I figure I might want to upgrade. Can I just go out and get any balancer for an externally balanced 400 and be good to go withouth rebalancing? I noticed the aftermarket ones are frequently less than 8", is this OK? I would guess this is OK, but wanted to verify. Thanks guys...

the outer ring can slip and come off when they get old, the rubber on them separates from the metal .you can buy a balance cover from summit that will keep it from flying apart for about 20 dallars.im no expert at all but changing balancers could change the balance of the motor if it was perfesionaly balanced.if i was worried about it i would buy new stock balancer and put the summit cover on it

I used one of the inexpensive aftermarket balancers on my stroker motor initially. With a loose 5000 stall converter it revved pretty quick smile.gif The keyway in the crank and the balancer started to wear and a vibration developed. I caught it early and no damage was done. I run the 7" ATI and have had no problems.

Greg,
To answer your question ... As long as the shop that originally balanced your engine did not do anything to the damper, you should have no problem replacing it with a new one. All of the 400 dampers are supposed to be manufactured to the factory imbalance spec, and should be interchangable without any balance problems. Same goes with flywheels by the way.
I will mention that I have seen several of the "less expensive" dampers that were way off the mark as far as balance goes. If you stick with a good name brand such as ATI, BHJ etc, you should not have a problem. Pioneer also makes a nice line of street and strip type dampers that are moderately priced, but very nice.
Hope this helps,

Thanks guys, I appreciate the quick responses.

Bill, any idea where I can find Pioneer balancers?

i needed to change a balancer on a previously balanced engine (406) and like you i was concerned that by changing this key element of the balancing package it might have a detrimental affect. so i bought a new balancer, took it and the old balancer (which had not slipped) to a balance shop and they balanced the new one identical to the old one. installed it and so far everything is fine.

i guess to make that clearer i should say they replicated the "im"balance of the old one in the new one. if they just balanced it without reference to the other dynamics it wouldnt have accomplished anything.

Competitionproducts.com has the pioneer balancers. http://www.competitionproducts.com/2004CompProducts.pdf

I got an internally balanced 8" SFI Pioneer for like $160 from them.


Part # HB400 = SB chev 400 Ext bal 8" $60
Part # HB400s 8" ext bal SFI $100
Part # HB2024 ext bal 8" 169.95 (BEST BALANCER!)
SFI 18.1, etched timing marks, cnc machined 1045 steel, tested to 12,500RPM.