Water Pump Pulley

[Jimmy G.]

Anyone ever used a small block WP pulley on a big block??. Driver stuff not judging i.e. 3900434 on a 427 - 390 hp car 1967

[Joe L.]

Re: Water Pump Pulley

Anyone ever used a small block WP pulley on a big block??. Driver stuff not judging i.e. 3900434 on a 427 - 390 hp car 1967

Jimmy-------


GM rarely used the same waterpump or balancer pulleys on both small blocks or big blocks. In fact, I don't know of any case in which a particular balancer pulley was used on both small blocks and big blocks. However, there is one case I know of for which the same waterpump pulley was used for both small blocks and big blocks. That case involved the GM #3848904. It was used for 1968-69 L-88, other early 1968 big blocks, as well as certain 1964-70 small blocks with SHP. So, in at least the case of that pulley, cross compatibility between big block and certain small blocks is assured. The 3848904 is a deep groove pulley. Presumably, some other small block, deep groove pulleys would work on a big block although they probably would not provide correct drive ratios due to OD differences. The 3848904 was discontinued in September, 1972 and replaced by GM #3995641 which is also now discontinued.

[David L.]

Re: Water Pump Pulley

Pulley #3900434 appears in the 1967 Corvette Assembly Manual (UPC K19, sheet A5.5). It was also used on other 1967-1968 models.

Dave