Another stupid question.. What is the difference between a long and short water pump and which do I have on my 84 Z?

you have the long pump, but you can use either on your engine. Moroso makes a spacer kit.

The difference is their length. (stupid answer)

Your accessories require the long pump. The short one doesn't have the places to bolt either your alternator bracket or your power steering pump. The spacers are only good for moving a belt-drive fan closer to the radiator in a car with early-model accessories, or none at all.

------------------
"So many Mustangs, so little time..."
ICON Motorsports

he didn't say he had accessories.

What would be the advantages of one or the other. Keep in mind southern Arizona is extremely hot, and stealing a little power to provide extra cooling is a good swap here.

it's not a big deal, but

if you're a racer, you have a much bigger selection of performance/aftermarket pumps that only come in the short version.

The short one is also lighter, and it's.... well, shorter, so it doesn't take up so much space. Handy in altereds and other misc dragster classes where engine length can be an issue.

------------------
"So many Mustangs, so little time..."
ICON Motorsports

Gotcha