What backspacing for a 15x7 on a 70

[callys]

I want to box up the factory 14 inchers on my mach 1 and go to Magnum 500s. I plan on using 15x7s all around, what backspace are you guys running? Or what is the standard one to run?

Thanks

 

[rbohm]

generally a 15x7 wheel has a backspacing of 3 3/4 - 4". some as much as 4 1/4".

 

[grego37]

if its an option, you can go wider on the wheels,
the 69-70 mustangs have lots of room for big rubber

 

[callys]

Trying to keep a fairly stock appearance as the car is all original and all stock, thanks for the info rbohm.