'60 crank balancer

[Dave T.]

What is the correct crank balancer for my '60 fuelie 290hp?? I was told on a judging sheet that the one on there is for a low hp engine. I don't see it specified in the Assembly Manual or the Judging Manual.
Thanks in advance for replies.

[Joe L.]

Re: '60 crank balancer

Dave-----

The original balancer for your 1960 290 hp FI application was GM #3764318. This balancer was 6-1/8" OD. It was a "stepped" balancer but NOT like the "stepped" balancer used for lower HP applications. The lower HP applications used a balancer that had the smaller "step" on the front of the balancer. The smaller diameter front "step" is rivetted to the rear.

The balancer used for your application was also "stepped", but the smaller diameter "step" was on the rear. In this design, though, there was nothing rivetted. The "step" was produced by the outer balancer ring being "turned down" for the rear half of its thickness. The balancer is "open" in the front with three "holes", just like the configuration of most later balancers.

The GM #3764318 was discontinued in November, 1962 and replaced by GM #3817684. That balancer was discontinued in November, 1964 and replaced by GM #3861968. In turn, that balancer was discontinued in Novemeber, 1965 and replaced by GM #3861970. Finally, the 3861970 was discontinued in June, 1971 and replaced by GM #3896904. That balancer remains available to this very day. Basically, the 3896904 is just like your original balancer EXCEPT that the rear half of the outer ring is not "turned down" to create the "rear step".

[Loren L.]

Joe is correct that it steps DOWN as it

goes to the rear; the outer ring is about 5/8" thick as I recall and I think the step down is about 3/4" - THERE ARE NO HOLES DRILLED IN THE OUTER RING.

[Jerry C.]

Re: Joe is correct that it steps DOWN as it

There is a picture in the 58-60 JG. To make a correct one you must buy a repro and fill in the outer holes. I tried all over the country to find one in the JG and no one has them. Everyone told me GM used three different balancers but NCRS only judges one as correct.

[Dave S.]

Re: '60 crank balancer

Is the #3764318 290 HP balancer from 1960 the same as the 315 HP balancer used in 1961. ?????

[Dave T.]

Re: '60 crank balancer

According to a few parts catalogues I've seen, yes.
Dave

[Loren L.]

If you fill in the holes, you still have a

balancer that is 1/2" too big in diameter - the blueprint for #3764318 was dated 7/17/58 and was still being revised up until 10/25/62, so I would seriously doubt that "3 versions" of the balancer exist.

[Loren L.]

Yes, per the 1 July 1961 Parts Book *NM*