From what I've looked into, there's two different types of water pumps - one is the short one, the other is the long one. Sounds like you bought a short one when you need a long one (by length, I'm referrring to the nose length).
Now here's something useful I've used in the past. Since your pulley setup is out of a truck and you bought a water pump for the mustang, it's not surprising that it won't line up - they're two different applications. If you go to
www.rockauto.com, pull up the '72 F-100 and bring up the water pumps in the listing menu. You'll notice that the part #'s listed are actually clickable links. Click on any of them, and it'll bring up a list of any application that particular water pump would work on. I use that to check interchangeability sometimes.
If you don't find what you're looking for that way, if you click the '68 and later mustangs, the 302's are listed so you could check interchangeability there as well. Hope that helps.
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2003 V-6 - the usual bolt-ons. Gremlin taking up residence in the idler pulley. I'll finish this one when I'm done with the other one.
1965 coupe - Born - straight six standard issue
Now - 5.0 motor, T5
tranny, R&P, full length subframe connectors, draglink bars, hedman headers
Coming soon - disc brakes, electronic ignition and a whole host of other stuff I forgot to mention. The list goes on and on. Basically, it's my new toy
