The SB in my car has the forged steel crankshaft installed in place of the cast crank it replaced. I'm running the 6 3/4 inch harmonic balancer in place of the 8 inch. I will pull the engine soon for a rebuild and was thinking of going with the correct 8 inch balancer. While at the Chevy dealership the other day to pick up a part and a GM Performance Parts catalog a conversation with the parts guy ended with him saying that the 8 inch harmonic balancer won't fit engines in '63-'64 cars because of not having the frame "notch", for clearance, as in '65 on. Is this correct .. ? .. I thought all SHP cars came with forged cranks and 8 inch harmonic balancers. ? .. Is running the 6 3/4 inch balancer not advised to use with the forged crank .. ? .. I never noted any problems in the past with the 6 3/4 ..

mrg

 

I would think they came with the 8" units in at least 64. My 65 L76 is the same basic engine as the 64 L76. My SHP 365hp car has the 8" balancer.

Mark

 

He is wrong! The 8" balancer will fit fine. Just make sure you have the matching timing chain cover. Rich

 

I is really interesting to see the misinformation that is "out there". First lesson...never believe the parts guys that are in the dealers today. VERY VERY few were even ALIVE when these cars were around. They are more informed about the ground effects bolt ons and under car neon lights in most cases than they are about ancient history cars like mid years.

8 inch balancers were used with SHP engines. 6 inch balancers were used with all the other motors. Since the cranks (steel in SHP engines and cast in all the others) interchange from a fit and balance point of view you can use the 8 inch balancer with the cast cranks. In fact you can use the 6 inch balancer with the forged crank. Beware as mentione above ...the timing covers are different in some cases even between sucessive years that used the 8 inch balancers. 350 balancers (8 inch) are different than 327 8 inch balancers so one has to be careful.

The frames changed in 1965 with the introduction of the BB engines. A divot was needed in the crossmember to clear the big balancer on the BB engines.Your parts guy it sorta right kinda sorta half right I guess.

Try to get an old parts book. It will tell you alot about what fits with what. Track down the application or the part number you are interested in and you can readily see all the places the part was used. If you have the Vette parts book and the "all other cars parts book" you will see that parts are used WIDELY across the GM products. It might be an eye opener for a lot of people to see that soooooo many parts interchange from mundane Chevelles and Novas to the vaunted top of the line GM flagship Corvette. When you see the prices places charge for "Corvette" parts that are used eleswhere it is another eye opener. The General very seldom spent a dime designing and tooling up for a single usage part unless it was 1000% necessary so expect to see a lot of commonality across the various engines and powertrain combos.

 

Thanks guys for setting it straight. I think that parts guy would have taken an "oath" to back up his claim about 8" balancers not fitting pre '65 SHP engined cars, the way he stated it. He meant well, but was wrong .. Ok ..
Oman - I know what you mean about "across the board" parts, so to speak. In this case it was across different GM makes. The part I was picking up from that same parts guy at the Chevy dealership for my Grand Prix was about 40 bucks more at the Pontiac dealership for the same GM part .. :smash: