Harmonic Balancer Application

[Mike B.]

The photo shows two early SBC harmonic balancers; one with perimeter holes, the other without. Both have the pully attached by three 3/8" NFT bolts. I'd appreciate some of the experts opinions on the correct applications, especially as it pertains to Corvettes. Thanks in advance, Mike

[Henry A.]

Re: Harmonic Balancer Application

I believe that the one on the left is original and the one on the right is over the counter...the holes are for weights to balance the harmonic balancer. They are for low horsepower small blocks...I know that it was used for the 283 and the 327. In 1963 it was used on the 250 and 300 hp cars.

[Timothy B.]

Re: Harmonic Balancer Application

Mike,
This was discussed a while back and my memory tells me the one on the left is used up to +- 1965 then the balancer on the right started showing up on low HP cars. My 63 has the one on the left and I am almost certain my 67 like on the right with the holes. I don,t know why the holes but Henry may be correct about balancing.

[Mike B.]

Re: Harmonic Balancer Application

I looked through the archives and couldn't find the earlier thread regarding application and years.

Regarding balancing, I believe the perimeter holes are not for that purpose. There are drilled divots on the rear side that by removing some mass at the heavy spots serve to balance the unit. See the photo below at arrows.

Any other opinions as to the applications?