i have a 89 5.0 with a five lug conversion. i added lincoln rear disc setup with lincoln axles. i'm getting welds but not to sure wat back spacing to use, i've tried a 15x8 with a 6.50 backspacing and the tires were too close for comfort near the pipes. and with a 5.50 there to close to the fender lip. anyhelp will be greatly appreciated