is a 6" X 3/4 balancer the right size for a 307? i believt eh current balancer is 6" diameter, but it looked like 2in width...is the 3/4 gonna be wrong and mess up the engine?

TTT, HELP PLEASE

i have a 307 in my truck when i get the chance this weekend i'll measure the diameter and thickness of the balancer. right now i'm getting ready to go out and it's cold i can do it tomorrow for ya

that would be great thanx, post it tomorrow if u have time please thanx

TTT

Blue, all the early sbc's use a neutral balancer harmonic balancer (exept the 400 which has a distinct notch cut out of the back side of the inertia ring). Because the SBC is internally balanced, it's not going to make or break the engine to use a smaller or larger balancer, within reason. Small balancers do not absorb harmonics as well as larger ones, huge balancers add a lot of rotating mass to the very front of the crank snout. The 6-1/4" x 1.75" balancer is one of the most common, and the next would be the larger 7-1/4" x 2" (or something like that) And even some 8" are available. You could use either as long as it clears the chassis, but DO NOT USE A HAMMER TO INSTALL IT, and just be SURE it's a neutral balance for internally balanced motors. I believe all balancers for the external balance 400 cu. in. motors were 8" x 2" (not positive on that one), but like I said, they have the distinct notch cut out of the back side that would make them obviously not a neutral balance.
Hope that helps.

Best way is to go to autozone etc ask for a balancer for a 307 and just measure it.

i measured the balacer today. i'm sure of the thikness it was 3/4" and becasue the pulley and all the other stuff down there was kinda in the way it was close to what marv davis said: 6 1/4".