The Stovebolt Site Forums The Shop Area Engine Shop 235 fan fit (not)

I wrote a long post about this problem.
First, the crankshaft pully is a differant diameter from 54 and earlier (smaller diameter) than 55 and later.On some trucks you can not use a 55 pulley because of an interfernce problem with a the front crossmember. If you try to use a 54 and earlier crnakshaft pulley and a short shaft water pump with a 55 and later water pump pulley (significantly larger in diameter) the water pump will not turn fast enough. So I finally went with the adapter plate and have no problems.

Another option I believe is that PATRICKS sells a a 55 and later short shaft waterpump with a 54 and earlier water pump pully on it so you can use your 54 and ealier pulley.

John Gott