i have a 86 iroc with wilwood front brake setup. stock wheels fit fine. iam going to order the welds should i go with a 3.5 or 4.5 back spacing on the front? my car has the mosor ford 9inch what back spacing should i go with on the back? 4.5 5.5 or 6.5?

 

weld RTS wheels come in.. low pad...med pad..and High Pad
to clear calipers. low pads will fit fine.as med pads move the wheel out more then enof.. front back spacing is up to you..

weld rts wheels come in a funny width..they add .275 to ea width
so a 9" wide wheel is going to be 9.275 wide and a 10" wheel is going to be a 10.275 wide wheel

as for the rts wheels for the backspace if you go with the 15x 8.275 wide rear
with a 4.5" back space you should bolt right up..

now if your going to mode to fit more wheel under the car.. check out my post. I show most everything you will want or need to know on the rts wheels.

10.275" wide rts with a 6.5" back space tire size MT sportsmen 12.5x29x15 all under fender

 

my car has the wilwoodfront discbrake bigbrake with 4piston calipers. i got a choice of 3.5 or 4.5 the rear is a moser ford 9inch seems the stock wheels set in too far.

 

forgot to add my car has drum brakes on the back.