What is the Biggest whelel/tire combo for a '74 E-Body?

[NotaHemi]

[What Size wheels/Backspacing for a '74 E-Body ]

Hey All-
I was just wondering. I want to put some large meats in the back on some weld wheels 15" ProStars. I would like 15x10's but have seen that these may not fit, so I may have to settle for 15x8's. I also would like some 28-30" tall MT ET Streets with about 10.5-12" width. What is the largest I can go and what back spacing would I need? Some say 4.5" some say 4.75" would be better. (I guess it depends on the wheel width). I don't want to relocate the springs or cut the wheel wells.
Thanks.

[JIM ROGGOW]

A GOOD TIRE AND RIM WOULD BE- 15 X 8'S W/ 5'' BACKSPACE, AND 275/60/ 15'S OR M.T. 28 X 10.50 X 15- YOU WON'T GET ANY THING MUCH BIGGER THAN THAT WITH OUT MODIFICATION. ALSO TO RUN A 275/60/ 15- AT LEAST 4 3/4 '' BACKSPACEING IS NEEDED.
YOU CAN RUN 15 X 8'S W/ 4 1/2'', BUT YOU MIGHT GET AN OCCASIONAL RUBBING. THE EXTRA 1/4'' TO 1/2'' BACKSPACE WILL KEEP YOUR TIRES FROM RUBBING ON THE WHEEL WELL LIP DURING SIDE WALL BULGE. CENTERLINE MAKES THE TELSTAR 13'S IN 5'' BACKSPACE, AND IN 8'' AND 10'' WIDTHS.

[NotaHemi]

Thanks, Jimbo. Just the info I was looking for.

[340MAN]

i run a 285/60/15 mcquery road star soft compound on a weld rodlite 15x8 with 4.5 backspacing.
it is a very tight fit since these tires have around 11.6 cross section & 10.2 tread patch.
i have about 1/4 in frt & 3/8 in rear against springs & about 1/4 to
make contact with wheel opening.
i run gabriel highjackers @ 45 psi for street driving & @ the track drop it to 20 psi. the shock within the airshock is great & have no traction problems.
i know this is the largest tire that i have been able to place under this veh without modifications. it is taller & much wider than the 275/50/15 i use to run.
hope this helps.