small block 8-inch harmonic balancer
 

Bought this when I was rebuilding my 350 but went with a stock damper instead. I installed it and removed it, nothing wrong with it and it was never run on the engine, just been taking up space on my shelf.
$85 + shipping and Paypal fee

Re: small block 8-inch harmonic balancer
 

Remember GM made two styles of this dampener. One with the key lined up with the timing mark and another that is offset. You didn't give the year of your 350... If you get the wrong one the timing marks will not line up with your pointer.

Re: small block 8-inch harmonic balancer
 

I didn't get the wrong one, just decided to use a OE damper instead. My 350 is a 1974- here are the specs on the balancer. https://www.summitracing.com/parts/pfs-80002#overview
https://professional-products.com/products/80002