I bought a short big block water pump for my 68 396 project and would like to I.D. it.
The casting # is 336100, it may be 386100, but I'm sure it's 336100
The part number on the GM box is 3990993.
Anybody know what this is for??? Thanks, Karl
I believe the 3990993 number is a new number for the short BB pump. Can't help you with the 336100 number, sorry.
Ed
An old thread in need of an update. Seems 386100 may have been the actual number and after doing a google, looks to be mentioned in 'Chevrolet by the numbers 1970 - 1975'
My casting - 3856284 which appears correct for 68 396.
What was the original shaft diameter? Mine has a 3/4" size, should it be 5/8"?
284 is the correct WP casting number for '68,
Jerry
Thanks Jerry, do you know what the pump shaft diameter for 68 L34 396 is - 3/4" ?
I'll have to check one for you when I have a minute.
Jerry
Just a prompt bump for Jerry or anyone on this shaft diameter detail as above
Hi Rob -
If I'm reading the drawing correctly in the book "Chevrolet by the Numbers 1965-69" the shaft diameter for water pump casting number 3856284 is .64" which is about 5/8" (5/8" is .625" to be exact).
Paul
The 284 casting was machined in two configurations. The one used on BB Corvettes from '65-'69 had the big bearing, a 3/4" diameter shaft, and a 5/8" pilot with a 3" bolt circle on the hub. Starting in '71, all Corvette water pumps went to a 3/4" pilot and a 3-1/4" bolt circle on the hub.