Pulleys--3864480 & 3906656

[George W.]

I see where the 656 pulley is used in '65 396 and '66/'67 427 applications, but I cannot find a reference for the 480 pulley. Any help? Thanks, G.

[Michael H.]

Re: Pulleys--3864480 & 3906656

George,

I believe the 3864480 was the original part number for the 65-66 BB water pump pulley but it was replaced some time around the start of 67 production with the 3906656. Not long after, all replacement pulleys for 65-66 would also use the later 67 part number.

[George W.]

Re: Pulleys--3864480 & 3906656

Michael, thank you. So I guess the 480 is "THE" correct pulley for '65/'66? Is there a points deduction for using the 656? Thanks, g.

[Michael H.]

Re: Pulleys--3864480 & 3906656

I'm not sure if there's a point deduction George. I don't have a 65 or 66 JG. Hopefully, someone that does have one can answer this question.

[Wayne M.]

Don't think any way judges can tell

The "480" has the part # stamped near the hub bolt holes, which are hidden by the flange of the fan clutch. The other "test" is to run your finger on the inside, under the where belt grooves are on the exterior, and there should just be a flat surface, not the mirror image of the grooves (as say on the SB high-horse "245" pulley).

[Joe L.]

Re: Pulleys--3864480 & 3906656

George-----

I'm sure that there would be a deduction taken for the use of the 67 pulley on 65-66 engines. There is a slight difference in the configuration of the "hat" section of the GM #3864880 pulley and the 3906656 pulley. I can't describe the difference, though.

Although both pullies are discontinued, I believe that both of these pullies are reproduced by the "Pulley King". However, your best bet might be to obtain one from one of his stocking distributors like Dr. Rebuild or Paragon.