I'm the one your Brother was talking to earlier bagged. If the
Allen Engine Development Kit isn't to your liking, a few of the guys over at
www.tccoa.com are also using the
FRPP blower with good results and even a few
Vortech S-Trims. There's also one guy over there running a 1.7L
Kenne Bell and although it does make some impressive power, it's not exactly cost efficient for our application. So if you don't like the idea of spending a lot of money, this one isn't for you.
As I told your brother, the '96-'97 4.6's were the best engines of the bunch and are essentially the same as the '96-'98 Mustangs, with the exception of true dual exhaust. Not to mention that if supercharging the car is in your future, the later engines are a better base to start from, as earlier ones require the '96-'97 upgrades anyway.
If you go with the blower and a couple of modest bolt-ons, 12's are cake. If you get creative with your blower combination and get the major bolt-ons on there as well as gear/transmission, low-12s, high-11s are possible. Beyond that, it's going to start costing you some big money.
If a blower car isn't in the cards, there's always nitrous. And in the same respect as the blowers, the Mustang kits will interchange with the T-Bird/Cougar engine. If you must keep it N/A, the PI head/cams/intake upgrade is good enough to get you into the 14's. You'll need most of the bolt-ons and some gear and transmission work to get it into the low-13s and you'll need to be really aggressive with things to get it into the 12s. Don't fret though, all is not lost. They can be made fast, you just need to overshadow the additional weight and IRS disadvantage (for drag racing purposes, anyway) that's presented, with more power and good traction.