Correct Pulleys for '63 327/300?

[Seth McCulloch]

Does anybody know what the correct harmonic balancer pulley and water pump pulley would be on a 327/300 without AC or power steering? Also any leads on tracking these items down would be great. I have come across a lot of confusion as to how many grooves these should have, the correct sizes, differences between high performance and special high performance, and other details. Thanks in advance,
Seth

[Steve D.]

Re: Correct Pulleys for '63 327/300?

Seth

Page from 63 AIM attached. Items 9 and 13 are pulleys.

Steve

[Steve D.]

Re: Correct Pulleys for '63 327/300? *NM*

[Joe L.]

Re: Correct Pulleys for '63 327/300?

Seth-----

I'm always reluctant to get involved in these pulley system configuration questions, especially for 63-67 Corvettes. However, I'll offer this:

The original crankshaft pulley for your application was GM #3744043. This is a dual groove pulley of 6-5/8" OD. It is still available from GM for about 50 bucks, GM list.

The original waterpump pulley for your application was GM #3790356. This is a dual groove pulley of 7-3/32" OD. It was discontinued in September, 1974 and replaced by GM #3900434. The latter pulley had a somewhat different shaped "hat" section, but was 100% functional for the applications it serviced. However, it was discontinued several years ago, too. I believe that the 3790356 is reproduced, though.

The diagram in the AIM appears to show waterpump and crankshaft pullies that are single groove. However, I believe that's an error. In any event, the pullies which the AIM specifies are both dual groove pullies as I've described. I think that the inner groove on both pullies for your application may be "vacant". GM didn't leave pulley grooves "vacant" too often, but I believe that this is a case in which they did.

[Seth McCulloch]

Re: Correct Pulleys for '63 327/300?

Thanks guys, this is excellent information and it appears to validate that my confusion is more common than I thought.

For what it's worth, it looks like Corvette Central sells GM 3744043 as part number "302370" and GM 3790356 as part number "302360".

Thanks again,
Seth