From the throttle body to the exhaust manifold , a Crown VicGrand MarquisTown Car 4 . 6 L is identical to a Mustang 4 . 6 L except that the plate on top of the intake elbow says 4 . 6 L instead of the running pony logo . You can find those way cheaper than one yanked from a Mustang and they ' re practically giving them away at self service pullapart yards . The problem is you need a transmission and rear suspension too , along with a V 8 wiring harness and PCM . If it ' s an auto then finding an AODE out of a 4 . 6 L CVGMTC or trucksuv shouldn ' t be a problem . If it ' s a manual you ' ll need to scrounge up a T 45 , TR 3650 or an aftermarket option like a 3550 , TKO or T 56 factory on 0304 Cobras too the T 5 won ' t bolt up to a 4 . 6 L , although it will bolt up to the old 5 . 0 but either one would blow it up anyway you ' d want a World Class T 5 for a 5 . 0 . The 7 . 5 rearend won ' t last behind a 4 . 6 L or 5 . 0 either so you need a 8 . 8 rearend either from a 9604 GT or you can retrofit the 9904 Cobra IRS . The only real practical way to do a swap would be to buy a complete , running wrecked GT to swap everything over from . As cheap as 9498 Mustangs are going for , you ' re almost certainly better off just buying a clean GT and swapping your refurbished interior into it than doing a engine swap .