1967 427 A.i.r

[Jeremy H.]

I need to know what the correct part number pulley for the water pump is on a 427/435 with A.I.R. and power steering? The belt I have for the water pump to crank is to long. I do have the short version. I might have the wrong belt? Is there a different belt to use for crank to water pump that is not listed in the parts books?

Thanks

Jeremy Hedges

[Joe L.]

Re: 1967 427 A.i.r

I need to know what the correct part number pulley for the water pump is on a 427/435 with A.I.R. and power steering? The belt I have for the water pump to crank is to long. I do have the short version. I might have the wrong belt? Is there a different belt to use for crank to water pump that is not listed in the parts books?

Thanks

Jeremy Hedges

Jeremy-----

In your case, the fact that the car is equipped with K-19 should make no difference with respect to the water pump pulley or captive belt between the water pump pulley and crank pulley. All 1967 427, except those equipped with C-60, used the same water pump pulley. It was GM #3906656 and it was a 2 groove pulley of 7-3/16" OD. The captive belt was GM #3837810 and it was of 3/8" X 34-3/8" in overall length. Except from reproduction sources, you won't find a belt of this length.

With K-19 (and without C-60), an additional single groove pulley was "sandwiched" to the front of the 3906656. This pulley was GM #3765427 and it was of 7-1/8" OD. However, as I mentioned, its addition had no bearing on the existing 2 groove pulley or the captive belt used.

[Jeremy H.]

Re: 1967 427 A.i.r

I have a 3 groove pulley for the water pump, is that wrong? If so, where do I get that single groove pulley that is "sandwiched"? I assume that that extra groove is for the smog?

Jeremy Hedges

[Joe L.]

Re: 1967 427 A.i.r

I have a 3 groove pulley for the water pump, is that wrong? If so, where do I get that single groove pulley that is "sandwiched"? I assume that that extra groove is for the smog?

Jeremy Hedges

Jeremy-----


The pulley you have is likely GM #3889372. As far as I know, for the 1967 model year this pulley was originally used only for L-36 and L-68 with C-60. Is it POSSIBLE that it was originally installed in your case? Yes, it's POSSIBLE, but I don't think it would have been TYPICAL of factory PRODUCTION.

The GM #3765427 pulley was "sandwiched" between the fan clutch hub and the 2 groove GM #3906656 pulley. The single groove 3765427 was used for the K-19 driver pulley.

Both the 3765427 and 3906656 are GM-discontinued. However, both are reproduced.

Keep this in mind: IF someone previously replaced the original 2 pulley set-up with the 3 groove pulley, I can envision 2 possible reasons for doing it:

1) The 3 groove, single pulley was used for all L1968-74 big blocks except L-88. Some folks THINK it was used for all 67-74 big block applications. If someone was "making up" a 1967 big block, they might have been among the folks that think the 3 groove pulley configuration was used for all 1967-74 applications;

2) The 3 groove pulley is of smaller OD than the 3765427/3906656. Therefore, it causes the fan speed to be higher. That, in turn, increases cooling (that may well be why it was used for 1967 C-60 applications and why it was adopted pretty much across-the-board for L68-74 Corvette big block applications). So, the 3 groove pulley does offer a functional advantage. Of course, not too many folks know about this, but one of the ones that do may have played a part in the history of your car.

[Jeremy H.]

Re: 1967 427 A.i.r

Thanks, great information.