backup water pump belt

[Merrill Anders 32014]

I have a 65 300hp 327. I bought a supposive backup belt to go on the pully from the crank to the water pump which is numbered
GM 3952336 (7/16 x 31.75. Is this the correct belt and if so what is the secret to installing it ?

[Joe L.]

Re: backup water pump belt

Merril-----

Well, here we go with another one of these 63-65 base or L-75 pulley issues that I hate to get involved in. But, here goes, anyway:

I'm not 100% sure that your application originally used a captive belt in the inner pulley groove position. However, IF it did, it did not use a GM #3952336 or any predecessor part number. The GM #3952336 is a big block captive belt originally used for 1969 Corvettes, but also applicable in SERVICE to 1968 Corvettes. It's not the correct length for any small block captive belt.

IF you application used a captive belt, then that belt was originally a GM #3845643 which is a 3/8" X 37-1/2" belt. That belt was discontinued years ago. You may be able to use belt GM #9433728 which is a 7/16" X 38" belt. Or, you may be able to get a reproduction belt from Quanta.

As far as installation goes, the easiest way that I've found to install one of these captive belts (and, I think that I've tried just about every imagineable way short of cutting the belt and patching it back together) is to remove the crank pulley. Then, install the belt around the waterpump pulley and the crankpulley. With the crank pulley flat against the balancer face, pull it down until the circular "lip" at the pulley center "snaps into" the balancer center hole. Then, rotate the pulley until the retaining bolt holes line up with the holes in the balancer. Install the bolts, torque to spec and you're done.

[John H.]

Re: backup water pump belt

My references may be incomplete, but I have nothing that indicates that a '65 327/300hp (L-75) ever used any sort of captive water pump-to-crank belt.

[Merrill Anders 32014]

backup water pump belt

Thank you sir you just saved me a lot of problems