jdmaris

I am working on an old '66 Corvette Drag Race car, now converted back to street. It has a ZZ4 crate motor. It seems to have a unusual water pump. The pulleys don't align up correctly. I measured to see if it had a long or short water pump. The pump measures 6 inched from the block to the outer edge where the pulley bolts on. Can anyone tell me the correct water pump for a ZZ4.

Additionally, are there any functional differences between the short and long water pumps. Could I use either one, with the correct pulleys?

I have included a couple of pictures. Can't identify brand/model





Anyone able to identify this water pump?





My measurement

mr.beachcomber

You need a Chevy short water pump to align the pulleys since the ZZ4 is mounting inside a '66 Corvette chassis. This PDF explains the difference between the long and short water pumps.

It appears that you may have an '84-'91 aluminum water pump installed on the engine right now. This won't work as all these pumps were to designed to run CCW with the serpentine belt setup.

Hope this helps. Have fun with the '66!

jdmaris

Thanks for your reply and help. Of course I did not provide all the specs on the '66. It was a drag race car and has a custom frame with lots of room for most anything as the motor has been placed 10% rearward. I also have found a small difference between the length of the long water pump. Edelbrock shows the long water pump as 6 15/16" and other places a 7". I am considering using a long pump so I can use the March Performance mid-mount alternator (#22043).

I want to ensure that this will not present a cooling issue. It now has a "performance" water pump pulley and the car over heats in slow traffic.

I am converting this car back to use the Crower 8 port injectors that was on this car when it was raced. To make this work on the street, I am putting in late model injectors and a FAST computer system. Just for fun I am attaching a picture.

mr.beachcomber

I believe that the actual figure is 6 15/16" (6.9375") so Edelbrock is correct. If you're going to use the long pump (see Stewart's specs), be sure to use a long pump's harmonic balancer pulley to ensure that your belts line up correctly. Given the engine set back, you should be good to go, but be sure to do a mock-up first to see if you clear the front suspension's stamped steel crossmember. (If I remember correctly, there was a depression stamped into the crossmember to clear the harmonic balancer/pulley arrangement.)
Here's a link to a tip from Stewart Components addressing that type of problem. Basically, you want your water pump turning the same number of rpm as the crankshaft on the street.


Hope this helps!