I have a 1976 Ludwig floor tom that I just got the bottom hardware for, and it's clear the drum is slightly warped.
The resonant head will not sit on the drum!
What can I do?!
Aquarian American Vintage drum heads are made oversized compared to modern heads and might work here.Another thing you could try is notching the collar of the head at 12,3,6,and 9 o'clock,with a hack saw,just enough as to not cut the drum head.I have done this over the years with warped or oversized drums and it works very well.
Steve B