what to do wheel will not fit

For 67,the track on the B is listed at 59.2 inches, vs 55.6 for the A. That is Plus1.8 inches per side.And the springs got kicked out .5" per side.I have no spec for the early As.As mentioned:Custom wheels for sure,now, or start cutting.

A 550hp 340 eh? That's pretty potent.I'm guessing it's stroked or supercharged? Or something like 400 plus 150Nitrous. In an early-A I'm thinking that calls for tubs and SS style suspension, and of course that leads to a narrowed rear,12s or more,and slicks.
I mean you have enough P/W to get into the low 10s, and your 4.10s are good to 130ish. You are gonna need some serious suspension to get there.
Man, that's gonna rock!