L-72 8" Balancer help please

[Glenn B.]

Anyone know if either of these 8" balancers remotely resemble an original 66 L-72 427?

Note the timing mark on the natural balancer is aligned with the keyway.

The orange unit has the timing line moved, maybe 8 degrees from the keyway? The orange one cam off the running engine.....

Thanks for any help you guys can provide.
Glenn

[John H.]

Re: L-72 8" Balancer help please

Anyone know if either of these 8" balancers remotely resemble an original 66 L-72 427?

Note the timing mark on the natural balancer is aligned with the keyway.

The orange unit has the timing line moved, maybe 8 degrees from the keyway? The orange one cam off the running engine.....

Thanks for any help you guys can provide.
Glenn

Glenn -

The orange one came from a 1969-up externally-balanced passenger car application - note the cast-in external balance weight. The timing index line on the inertia ring on those engines was offset from the keyway (matching the offset of the timing tab on the '69-up timing cover) as part of the new "long" water pump accessory drive system. Your L-72 is internally balanced - you do NOT want to use that balancer on your engine.

[Glenn B.]

Re: L-72 8" Balancer help please

Thanks very much John,

Good information, but it looks like that the external weight has been mostly machined off the orange balancer (when compared to a typical 454 type external balancer). Note the balance holes are drilled adjacent to where the little bit of extra "leftover" weight is. Perhaps it is an aftermarket balancer?

So could it be that the orange balancer is actually neutral balance?

Anyone know if the natural colored balancer is the correct for L-72? or could it be GM service part 3879623, which is shown for 67-69 427 engines according to my GM 2001 parts catalog.

Still not sure what the original 66 427 balancer actually should be.

[Joe R.]

Re: L-72 8" Balancer help please

Anyone know if either of these 8" balancers remotely resemble an original 66 L-72 427?

Note the timing mark on the natural balancer is aligned with the keyway.

The orange unit has the timing line moved, maybe 8 degrees from the keyway? The orange one cam off the running engine.....

Thanks for any help you guys can provide.
Glenn

Glenn,

Check this out:

https://www.forums.ncrs.org/showthre...70325&uid=1141

Joe