Ford made a 1" wedge-shaped spacer for the early-1960s T-Bird (also has pipes to flow water thru the spacer, handy)
Theyre on Ebay, IIRC I sold one for $20 or $25.

Depends how far off it is. If its only 1/8" or so from level, just run it, you can set the floats a little different to compensate if needed.