Re: how to determine backspacing?
i run rushforth 18X10's with 5.5" backspacing and leaf springs. the spring is not the limimting factor, it the inner wheel well. i have 3/4" to the innerwell at its closest pointat 5.5" backspacing. i would hesitate to go any further inboard without mini tubbing.
you can get more of a deep dish @5.5" of backspacing if you tell Jason to hold the pad width to one inch. The thinner the pad, the more outer rim is exposed. a thick pad forces him to move the center piece out to maintain the backspacing.
69 X-44 base coupe, ZZ4, 16lb nodular flywheel, Center force DF clutch + PP, Holley 600DP, Hooker super comp 1 3/4 ceramics, 2.5" dual exhaust w/ X-pipe, flowmaster 40 series mufflers.