Chris,
A 9" wheel won't fit my Valiant (74 front end) either, at least if it's got enough backspace to fit under the fenders. FWIW, my car has the same front end components as a friend's 68 Valiant, and he had to use a 1/8" spacer to fit *8"* Bullits, while my 8" Cobras have about 1/8" clear. Although I have no hard proof, I strongly suspect that some LBJ's are designed with different offsets to the arm end, OR perhaps have the OTRE stud hole machined in a slightly different location. There may also be some wiggle room in OTRE designs, but I haven't checked that at all. Don't count out anything when it comes to aftermarket parts.