Water Pump pulley -deduction ????

[Keith B.]

I'm despartely searching for a correct water pump pulley 2 groove for my 66 BB 427, non-air car, org # 4864480. I know it was replaced in early 67 with # 3906656. Since it does not look like I will find an org #4864480, I know Doc R and Paragon have #480 reproductions ($128).

Will these repro meet judging standards, if not how much of a hit will I take or should I find a replacement # 3906656 but this is a early 67 replacment part.

Lastly, judges opinions pls on this scenerio. I bought a one owner, org 39K mile car L-36. The org owner and I have regular contact, and 1966 calander YEAR car/engine pics of the car when he bought it. My car has a date stamped 3 groove water pump pulley on it, like a C-60 air car BB would have. Again my car is a non-air car. Org owner states he never changed the pulley (org water pump still on car). Is it possible the factory put this 3 groove pulley on for whatever reason??

[Peter L.]

Re: Water Pump pulley -deduction ????

Keith - You indicate the "car has a date stamped 3 groove pulley on it." Can you elaborate?

While it's possible the factory put a 3 groove pulley on the car, you're dealing with "possible original" (The ball's in your court on establishing originality. Do the 1966 photos show the 3 groove pulley?) vs "typical" factory production for a non-C60 BB.

Have fun. Pete

[Joe L.]

Re: Water Pump pulley -deduction ????

Keith------

I think you mean pulley GM #3864480 and not 4864480.

I doubt that the A/C pulley was originally installed on the car. For one thing, this would have resulted in an unused pulley groove which was rather uncommon in PRODUCTION. For another thing, as I recall, the OD of the A/C pulley was different than the non-A/C pulley. So, that would affect drive speed of components. Of course, it's always possible that it was used, perhaps a "factory mistake" or used "in a pinch" for lack of the correct pulley. Like Pete says, though, it's up to you to document it and that's going to be pretty tough.

Besides, even if it is a true anomoly created at the factory, I think you're better off correcting this anomoly and installing the correct part.

By the way, what's the number stamped on the 3 groove pulley?

Also, I think that you're better off getting a reproduction of the 3864480 pulley rather than using a 3906656. As I recall, the hat section of the 3906656 is slightly different from the 3864480. Also, the 3906656 is, itself, difficult and expensive to find. In any event, I think you'd lose more points for using a GM #3906656 than you would for a reproduction of the correct pulley, if the repro even receives any deduction, at all.