Trans crossmember 63-66 A body?

I don't think you need to use that, if your exhaust
installer can bend pipes halfway decent.

I have dual exhaust 2.25" under the tranny crossmember.

I don't hear any "hard times" with normal sized speed bumps.

I am not hitting on one nearby speedbump, that I did when I had my
67 Camaro; the headers hit the ground with that.

I am using 205/70/r 14 tires, whcih are the same height as my
stock 7.00x 13 spare tire.

The V8 Valiants came with 7.00x13. 1964 and newer.