Grudge match HELP!

This is just a thought,, 235/60/15 MT's or BFG's are 26" tall and will fit your (SUPER CLEAN by the way) Valiant and just right for the 3.91's. I have no comparison data on 1/8 mile, but 1/4 mile with 3.91's should put you throught the lights at around 6 grand.
Looks like the rest of the combo on the car is a good set up.
You have small bolt wheels,so if you use the 14x 5.5 steelies you may want to look up M&H ( or others ) as they have 14's that are 22/23" tall and will help in the 1/8 mile.This may be your best bang for the buck if cost is a factor.
You have everybody's blood flowing over this post giving us that "WHAT IF" factor. I did this years ago at Bristol against the Year One Camaro and got creamed 3 out of 3 but had great fun trying.Nothing like "Heads UP" grudge racing. Best of luck to you. Too bad we will have to wait months to find out what happen.......