Grab a 351 out of an old Torino 70ish punch it out 30 over throw some slugs in it, around 9.0-9.5 to 1 compression, stuff in a mild cam, decent intake and like a demon 600cfm carb and your talking something that could run in the 12's easy depending on the condition of your pony. Screw the power adders. Especially blowers, plus don't let a stupid freaking movie turn you away from NOS or a blower, most of those cars were just props and portray a scene that doesn't even exist. Let me know if you need any help on the swap I've done it before and it's very easy. You can use your existing
tranny. You could probably pick up a decent core and crank at the junkyard for like $100 bucks ready for machining. After you get it back from the machine shop you will have a good solid rock to build on. What ever you get, keep me informed. I loved that era of Mustang. I had a Capri 5.0 with the big bubble hatch. I loved that ugly car.