Depends on the year of the car. I think it was in 1968 that they went to the long pump on Chevelles (actually all cars but the Corvette). If the alternator is on the driver's side, use a short pump, otherwise a long. A 71 uses a long pump.
I think it was 69 Pat....my stock 68 chevelle SS uses a short pump..
Also, all of your other componets/brackets are matched to either the long pump, or the short pump.
If you change from a long pump to a short one, you'll have to change power steering, alternator, etc.
1929 Model A Coupe
All Stock Restoration Started.
68 Chevelle SS 396 4 spd. #s match
Needs Full Restoration.
I just measured it against the old one and it appears to be a short one. When I switched motors, I put on a new water pump cuz my old one was starting to leak. Now, all the pulleys line up and I don't have any PS or AC so can I keep the short one or are they different volumes on the pumps?
Don't believe so. Unless you get a high flow water pump. I ended up getting a nice high flow edelbrock short water pump to help keep my 402 cooler. But between the stock short and long, there shouldn't be a difference... it was a clearance issue in the early chevelles like my '67. If you're worried about flow, buy a high flow aftermarket pump.