Correct backspace for steeliness on '73 Roasrunner

[UKPlymouth]

I know it's an old question, but what are current thoughts on back spacing?
8 x 15 on rear
7x 15 front
Wheel Vintiques steels with dog dishes. I understand that rears are 4 or 4.5" but which is better and why and is 4" correct for the front.
Got to ship these wheels to the Uk so I can only afford to do it once and correctly!

 

[kb73rr]

I've got the same size wheels on mine. I can tell you that 4"F and 4.5"R will fit and not look stooopid. As to different backspacing, it matter of the wheel, the axle and spring you have and the profile of the tires you are planning to use. If you go much more than 5.25"R you might have clearance problems with your springs.

 

[UKPlymouth]

Thanks, my tire choice is 255x 60 rears and 235 x 60 on the fronts.

 

[kb73rr]

I have 255-60 on the back too - BFG Radial T/A. Here is a picture of the car on a lift so you can see what I mean about the clearance with the springs. It's actually a little more than it appears in this view. I measured it at approx 1".

 

[rav440]

i have 295 50 15s on mine with 4.5 back space 8 or 9 inch wheel and they fit perfect .

 

[UKPlymouth]

Thanks guys that clears things up nicely and with tire options noted.

 

[monkele]

I have in front

8x15 BS4,5 245/60/15

and back

10x15 BS 5,5 275/60/15

 

[UKPlymouth]

I do have a set of 295 x 50 x 15 which I can't seem to sell. Wondering about squeezing those under with a 10" rim. Opinions welcome.