Fan clutch mounting bolt pattern
Thread Starter
Burning Brakes
Joined: Jan 2013
Posts: 753
Likes: 111
From: Barnhart, Missouri
Fan clutch mounting bolt pattern
Can someone tell me when the mounting bolt pattern on the water pump changed from 5/8 pilot hole and 1 3/4” bolt pattern to the later 3/4 pilot hole and 2 1/8” mounting bolt pattern? It might be different on big block and small block.
any information would be appreciated.
thanks
any information would be appreciated.
thanks
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
I've had two 1971 C3 sbc base L48. Both had 3/4" pilot. I don't recall bolt pattern.
If you're trying to make a pump with 5/8" pilot fit a clutch with 3/4" hole???... you can cut a short bushing from standard copper pipe at home depot … I don't recall which pipe size but it ain't had to find.
If you need to space WP pulley Forward you can get spacer shims in 1/16" & 1/8" from Moroso, SpeedWay Mtrs etc. Many WP Hubs can be moved front & back if you have a press, take back cover off and are careful.
If you're trying to make a pump with 5/8" pilot fit a clutch with 3/4" hole???... you can cut a short bushing from standard copper pipe at home depot … I don't recall which pipe size but it ain't had to find.
If you need to space WP pulley Forward you can get spacer shims in 1/16" & 1/8" from Moroso, SpeedWay Mtrs etc. Many WP Hubs can be moved front & back if you have a press, take back cover off and are careful.
