[32phil]

This problem has been discussed many, many times on this forum.
On a stock unmodified Early V8
Check everything !
Start with tire pressure. Have all the wheels spin balanced. Look for bent rims, warped, damaged, deteriorating tires. Don't forget the lug nut holes.
Then do a super critical inspection of the rest of the front suspension. Pay close attention to toe in/toe out and Caster. Look for bent, worn, incorrect/missing parts.
On modified cars / Hot Rods All of the above applies.
The critical issue with cars with big rear tires and small front tires is the caster.
On my 32 Brookville roadster the issue was the caster.
I have previously posted about the death wobble happening on this car.
Basically, it was a fresh build (20 yrs ago) everything was new or 100% rebuilt including the 32 steering box. The best parts available. No Expense Spared.
With the big and little tires the caster had changed causing the wobble to occur.
There is a spacer that is available that mounts above/between the stock wishbone and the center crossmember. This drops the ball down and corrects the caster and stops the wobble. Please use the SEARCH Function on this site to read the monumental amount of discussion concerning the death wobble.