I like how you guys politely tease me sometimes. I am the person who started this post. Maybe a better question for me to ask is whether or not I have to modify anything if I find a 17-inch rim for the front and back. I don't know much about cars and I'm learning as I go but I do know I don't want to change a bunch of suspension pieces out to fit a 17 inch tire.
I don't know why picking a rim is so hard but I like the look of a lot of your cars who have the 17 inch rim on the front and back.
I also like the old hot rod look of a big tire in the back and the small one up front but I don't even know what size of a rim you would run on the front to have that look.
Right now I have 15 inch Mopar Rally rims on the front and back and I have a 275 60 tire on the rear and a 215 65 on the front and I like that look, however since I'm going away from stock on mostly everything else I'm thinking it might look kind of cool to put on an after-market rim.
I'll go dig around on that tire thread.
Thanks
Polite teasing is part of what makes this a neat place to hang out.
So now you see why I said what I said. There are a lot of personal taste criteria that factor into choosing a wheel and tire combo.
A wide variety of factors go into making sure a combo fits without extensive mods. You can fit a lot of tires sizes and different wheel combos on the stock set up without changing hard parts. The key to it all is understanding the wheel dimension that allow this. IMO, the first place to start would be drawing/graphing out your current combo of wheel size, backspace, offset as well as tire sizes and measurements and then measure space to critical components like fender lips, inner fenders, leaf springs in front and back of the tire ( E body springs are not parallel), etc with the suspension at full turn, compression, etc. Also check all four wheels as there are variations from side to side on these cars due to original assembly tolerances and 40 years of use, abuse, and changes.
With all this info you can then compare a wheel or tire you are looking at against your current combo to see where it is bigger and may be close to various components and decide if it will safely fit.
For example, your 15x7 Rallye has 3.5 backspace with a 275/60 tire and 3" amount of distance to the rear section of the leaf spring ( just making up numbers here). If you change to an 8" rim with 4.25 backspace, your space to the spring has now been reduced .75" to 2.25" Changing the 275 tire at 10" section width to a 295 at 12" section width with that 8" rim means your tire is 1" closer to the spring (2" wider overall, 1 " per side) so you clearance now is 1.25". Basic math, but you have to visualize it all.
Or you just beg, borrow,steal a rim sizing tool, bolt it to the hub and calculate the max size you can get.