I have 225-60-15 all around on my 350 Gt with stock lace rims. If the tire fits ok in the car, the 7 inch wide stock rims will take up to about a 255 wide tire.
------------------ Tom Suffolk, Va 87 GT 350 5 spd.
When I bought my '86 1/2 GT, it had and still has 205/60R15 all around, on the 15"x7" honey comb wheels. The stock space between the top of the tires and wheel-well, in my opinion, made the car look like it was on jack-stands, and the rear looked ridiculous. Because of this, a set of Eibach lowering springs was one of my first up-grades. This made all of the difference in the world in looks, but the rear still looked bad, due to the 205's in the back. It even makes the car sit lower in the back, which really looks bad. I ordered a set of Falken 912 all weather tires all around. I want to fill the rear wheel well without making it look like tractor tires, like some cars I've seen...lol. I thought the 235's would look best in the back, but I feared the distance between the tire and strut might be to close. I chose to go with 225's in the back and 215's in the front, because my son's 225/45R17's cleared the struts by only about 3/8". So, if my new 225/60 R15's clear the strut with plenty of room, I'll probably go with 235's in the back the next time. I think maybe 235/65 R15 might be the solution for looks, but I'm afraid to go that big, and have my GT look like I've got tractor tires in the back. The vertual tire programs, on line, just aren't accurate enough to tell the story. Less Schwab's in-store computer does the best, that I can find, to kind-of show it pretty good, but it's really hard to find the solution. I wish some one, in the know, would publish tire applications on stock and lowered GT's along with pictures, so we new-comers, had some sort of guide to go by. I'll report back with my opinion on how my car turns out, and some pictures, to help others make their decision. Later...Michael P.S. wish me luck.