Summit need you to measure your backspacing to get drag rims. Is there some conversion factor or something b/c the backspacing is different for the front and back wheels in LT1 f bodies, but if I measured the backspacing using stock wheels, wouldn't the numbers all be the same?

Also, what size tires would I use for 15"X6"?

 

Required backspace varies with the width of the wheel. What size wheels are you trying to put on the front and the back. For example, a 15x10 wheel in the rear requires a 7.5" backspace. A 15x8" wheel requires a 5.5" backspace. 15x3.5" front runners only come in 1.75" BS. All that info is in the FAQ post on the Weld wheels.

 

Read the sticky...but how does the backspacing on my current wheels equate to different backspacings for different wheel widths?

Also, SJM said a 15x6, 15x8(or 10) set up would not work out well. They said the front would hurt at the strip due to more tire in front and be too weak for the road due to being too narrow. Thoughts?

 

The stock wheels are 8" wide. They have about a 6-5/8" backspace. The 9" wide WS6 and SS stock wheels have about a 6-15/16" backspace. You don't have to match the backspace, since most people want the wheels a bit more toward the outside of the fenders than the stock wheels.

There's a table of acceptable offsets in the FAQ. The offset can be used to calculate the approximate backspace.... I think I explained how in one of the FAQ's.