Make sure you are using header bolts..with small heads...usually need an open end wrench to tighten them up..

and yes..good head is hard to find...

and what kinds of heads are you looking for...small block big block ..hemis...slant 6?

Tony

70 AARCuda Vitamin C
71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield)
71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas)
71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)