8 3/4 bolt pattern question

You can do a lot without cutting the car. Spend some money on good springs and shocks. Don’t try to use old slicks, they seldom hook very good.

and BFG radial TA’s forget about any traction for racing,
I agree, but want to add also that you can roll the lip, and with the right offset, easily fit a 275-60R15 in there. Same inner and outer wheel houses as a 67-69 barracuda. I bet you can even fit wider without modifying the wheel houses on it. Once you cut n move the wheel houses, and spring relocate, it's a lot harder to put it back to stock if you decide on that later. Ask me how I know.