What is this???
 

Came off of a V6 but which one is unknown. The 4 bolt pattern matches 4 of the 6 bolts on a 305. But this seems to be a Harmonic balancer. So this must mean that the crankshaft flange bolt pattern is the same on all V6's ?? It seems to be two pieces. A pressed steel piece and a heavy solid piece with one balance hole it. Rubber in between. Fits inside a cast 3 groove pulley I have with the same 4 bolt pattern. There are no timing marks on it. The inside groove of the 3 groove has a timing slot. The only marks on this piece is a stamped "HT".
This will only fit on the crank one way. I assume that is so the timing groove is positioned correctly on the keyed crank hub and not for external balance. I guess it is stand alone balanced, like for an externally balanced motor. It came with a 3 pulley set. Can someone explain this piece and what motor it is for? All input and opinions welcome. I intend to sell this stuff and don't want to mislead anyone. I was told it came from a 65-66 GMC 305 V6 but I am now thinking the fellow was wrong about motor size? Also I think I read on here that there is a "balancer" that is not a harmonic balancer on some motor? I know that 305 and 351 do not have a balancer.

Re: What is this???
 

it could be off a 379 or a 432, both are externally balanced, according to Pete Chronis.

Re: What is this???
 

Tried to contact him by PM. No response yet. Probably busy.