If you're racing a hopped up TurboCoupe, SuperCoupe, or SportCoupe you're going to have your handles more full than you might think.
If it'* modded out, they're pretty quick. I think the best time I've seen a TurboCoupe run (off the bottle mind you) was a 12.8. With some tuning and a shot, it'd probably hit low twelves. And that'* with the 4-banger.
The Cougar XR-7 (Same as a SuperCoupe) my buddy has runs a 12 flat no nitrous.
I have to disagree, here. The Turbocoupe 4 was the same engine that they used in the Mustang SVO. I've run a few of those back in the day (I worked as a lot porter for a Ford dealer in high school) and I can say that they are not what you might claim. Unless the turbo has been replaced with the larger version with the water intercooler, it won't do better than mid 15'* on any day, which is what some of our L36'* do (mine does 14.9 regularly - without NOS). The stock gearing in the trans and the rear were crap for off-the-line launches. The Tbirds were much heavier than the SVO and that made for a higher 1/4 time, no matter what you did.
Giving it a good ole shot of juice at about 40MPH after just dropping it into 2nd might give you low 14'*, even high 13'* IF you ported the heads and modded the exhaust a bit. I'd loved to see the mod list if these are really doing 12.8. I have a couple of friends who run SVO and TC'* that would love to get those numbers.
The SuperCoupe had a similar engine to the Series I L67 and it had similar numbers across the board...weight, boost, HP, torque. Since there is only 1 Bonneville around that does a 12 second 1/4, and it'* a Series II that is seriously modded, I'd ask your friend where he runs that monster and how much he paid Coy Miller
for his underhood work. Coy and his crew do some of the baddest Ford 3.8L mods around (440HP@5300RMP / 490FTlbs@2600RPM - RWD) I'm sure Scott (BadSSEi) is up to a challenge!