Yea but once you get into the heavier mods you'll need either Summit or Jegs

 

I don't think the Crown Vic motors are internally different (those with PI heads, I mean). The HP difference was in exhaust and intake and perhaps computer tuning. Nonetheless, you should be able to find a motor from a totalled out Mustang for relatively cheap. Just try to go with one that has fewer miles than your car, if possible, or order a reman. engine. If it were me, I'd put in aftermarket cams while the engine is out... A mild cam will wake the car up a lot. I plan to do that eventually, but it's not as easy in the car.

 

Pretty much what he said, the PI cars you mentioned have a less performance oriented exhaust and intake, thus the lower HP. However I doubt that it's 50 HP less...at any rate, if you stick your PI intake and exhaust manifolds on....say a Town Car's long block (No manifolds or accessories) you will still be at whatever HP level you had in the mustang originally.

 

2000$ is a stretch for doing a 4v swap unless you get the motor real cheap because you have to factor in alot of bonus parts, such as wiring and ecu. If you need a dyno tune thats gonna add to the cost. Flywheel depending on which motor you use, cables, and other small things.

 

^+1 to what Uber said.The 4v will def make more power tnan a 2v all things being equal.Depeding on which 4v you're looking at some of the parts are getting hard to find and fairly expensive.If you want to make all the power you can, the 4v is the way to go.IMO