66 water pump pulley

[John F.]

I'm a little confused. I have a 66 coupe with 327/300 and Power Steering. The NCRS Tech Manual indicates that the Water pump pulley is a two grooved pulley. However the AIM clearly shows that there was only one belt routed from water pump to alternator and balancer pulley, and the diagram seems to show a single groove Pulley. The PS pump is run solely off the balancer pulley. What's the correct configuration for the WP pulley? Thanks

John Farren

[Joe L.]

Re: 66 water pump pulley

John-----

I believe that your application originally used a 1 groove water pump pulley. The original part was GM #3788472. This part was discontinued from SERVICE in April, 1967 and replaced, for SERVICE, by the 1967 PRODUCTION set-up. This consisted of pulley GM #3905995 used in combination with pulley reinforcement GM #3720616 mounted on the OUTSIDE of the pulley. Both of the latter parts are still available.

[Henry J.]

Re: 66 water pump pulley

John, don't feel badly. You are not alone. There appears to be a good deal of confusion about the pulleys, number of belts and the belt routing on 66's. I've been compiling information on this for a long time in an effort to get to the bottom of this.

Based on the information that I have collected from various sources, I believe that the information Joe Lucia posted in response to your question is absolutely correct...as usual!!!