foundvettelifeisgood

I bought a billet power steering pulley, a stock pump and brackets a while back in anticipation of hooking up Steeriods in my car that came with manual steering. It all went in nicely, but the PS pulley did not line up with my existing pulleys. It looks like if I were to get a 3 groove crank pulley, the PS pump pulley would line up.

So I was looking through a March Performance pulley brochure. There's a drawing of a short and a long water pump with measurements from the block to the fan mount face of either 5-5/8" or 7" respectively. The drawing shows that the water pumps are styled and shaped a little differently as well. In the drawing, the long pumps nose is like a beveled ice cream cone. The short one is rounded.

I've assumed that I have the long pump, because my car is a 72, but it has a Jasper replacement engine. I measured to find that my pump is 5-5/8", but it has the same ice cream cone nose style as the drawing of the long pump. :confused:

Summit's catalog suggests that the short pump was used through 68. So before I make the potential mistake of ordering short style water pump pulleys for my 72 that should call for long style water pump pulleys, I'd like to hear your thoughts on this.

Anyone seen the difference in the short vs long set of pulleys? I assume they protrude differently, but woundn't the alternator pulley be in the same plane regardless of whether the car had a short or long water pump?

:cheers:

theandies

All Corvettes 68 thru 82 with a SBC came with the short style water pump unless Bubba changed it and installed a long one. I don't know about BB's but I think they came with the short style also.

Paul L

FWIW, this is a #330813 waterpump with the correct 3/4" shaft. "Chevy" pumps have a 5/8" shaft. This was used 1973-1982. Note the reinforcing ribs on the snout. Just a few other notes:
-1968 to 1970 SBs used a #3782608 pump. These have a smaller-diameter front bearing than 1971 and later so the snout of the housing is smaller. Also the snout does not have reinforcing ribs and the top of the pump housing does not have a boss for a bypass hose fitting.
-All 1971 and those 1972 SBs assembled through approximately the end of may 1972 use #3991399 pumps. These have reinforcing ribs and larger diameter front bearings (hence the 3/4" shaft) than 1970 pumps.
-1972 SBs assembled after approximately the end of May 1972 use #330813 as in 1973 and later.

BSeery

Yep -- C3's were a short water pump with a 3/4" shaft.

BSeery

Yep -- C3's were a short water pump with a 3/4" shaft. I would think you could use short style pulleys and if need be, drill out the center hole on the water pump from 5'8" to 3/4".

foundvettelifeisgood

Thanks for all the help everyone. The puzzling thing is that Summit sells pulleys for 1955-68 small chevy with short water pump, and 1969-85 small chevy with long water pump.

Then they have a special MCH-5070 for 1971-82 Corvettes. No word on whether they are short or long pump style, but from what you guys have said it must be short style.