Crankshaft & Waterpump pulley ID

[Pete Lovrovich]

I have two pulleys that I am trying to ID that came with the array of parts I recieved with my 66. The water pump pulley number is 3995643 CT (there is an M8 and 31 stamped on the opposite side. The crankshaft pulley number is 3923898 (a 2A and BT are also cast or stamped into the same side). Any ideas as to the year and usage of these?

Thank you for any response.
Pete

[Joe L.]

Re: Crankshaft & Waterpump pulley ID

Pete-----

The GM #3995643 is a waterpump pulley applicable to many Corvette applications. It is a SERVICE replacement pulley which replaced original PRODUCTION and SERVICE pulley GM #3890419 when that piece was discontinued in December, 1971. It is a 2 groove pulley of 6-5/16" OD. Corvette applications include:

66-68 Corvettes with L-79, N-40, and C-60
68-70 Corvettes with base engine and w/o C-60

There are also some other non-Corvette applications in the 66-68 time frame. The GM #3995643 pulley is still available from GM.

GM #3923898 is a crankshaft pulley used for 1968-69 series 10-30 trucks with small block and N-40. It is a 2 groove pulley. It has no Corvette applications and is GM-discontinued.

[Pete Lovrovich]

Re: Crankshaft & Waterpump pulley ID

Joe,
Thank you for the usefull information.
Pete