69 427 pulleys and belts

[John C.]

I'm going through my 69 big block car which bubba has owned in the past and I'm trying to figure out if what I have for belts and pulleys is correct. Car is a mid Dec 68 (vin 10xxx) build.

The balancer pulley is pn 3921923 and the water pump is 3889372. I don't have a 69 AIM available right now but looking in the 68 AIM these seem to be correct. Can someone confirm the numbers are the same for 69?

Also puzzling is the balancer pulley on my car is stamped steel and the Paragon catalog shows a cast iron pulley as being correct on all bb cars from 65 through vin 24000 in 69. Which is the correct balancer for early 69?

For the captured belt I have pn 6654220. It is quite narrow compared to the other belts and it fits quite loosely. What is the correct application for this belt?

John

[Greg L.]

Re: 69 427 pulleys and belts

John, I'm not sure about your belt issue but my balancer pully is a 3921923BM and water pump pully is a 3889372BF so yours should be correct. My L36 was assembled Jan 16/69.

I think paragon is wrong in saying that it should have a cast pulley on the balancer for your application. The only cast pulley I have is on my power steering pump.

[John C.]

Re: 69 427 pulleys and belts

Greg

Thanks, I'm real glad they are OK as wow are they expensive.

What color is your water pump pulley? Paragon shows both a black and an unfinished alum pulley available.

John

[Joe L.]

Re: 69 427 pulleys and belts

John-----

The GM #3921923 (stamped steel) and the GM #3863108 (cast iron) are functionally interchangeable. For 1968-69 the 3921923 was used for most big block applications with the exception of some SHP and HD applications.

For 1965-67, the 3863108 was used for all big block applications.

For 1970-74, the 3921923 was used for all big block applications except 1971 LS-6 and 1974 with C-60.

All waterpump pullies were either painted semi-gloss black or black phosphate-finished. None were aluminum and none had any sort of "natural" finish.

[Greg L.]

Re: 69 427 pulleys and belts

My water pump pulley was a semi gloss black so that was what I restored it too.

Joe, does there seem to be a pattern, calendar wise, for when this pulley was painted or plated....or was it just at random depending on the supplier?

[Joe L.]

Re: 69 427 pulleys and belts

Greg-----

I know of no pattern. The VAST majority of these that I've seen were semi-gloss black painted.

[John C.]

Re: 69 427 pulleys and belts

Joe

The car in question is a HD L88, so is it possible to be correct with the #3921923 or does it have to use the #3863108?

Thanks

John

[Joe L.]

Re: 69 427 pulleys and belts

John------

GM says that early 1969 L-88's used the GM #3921923; later used the GM #3863108. Just when the change-over occurred, I do not know.