Ok what's the biggest size to fit on the 15" 10 holes?

[Unit 5302]

The biggest you'll be able to go on the front with possible rubbing is 245/55 15's. Even those may rub a little at full lock, you may want to buy a steering limiter kit to prevent it. The 245/60's will rub for sure. If you had a '91 the wheel wells are a little better, you'd be able to pull the 245/55's for sure no problem.

I don't think you can fit anything bigger than maybe a 255/50 15 on the 10 hole rim safely. If you go to a higher aspect ratio you could, but then it'd throw your speedo out of whack, and I think you'll need to mount the quad shocks backwards for clearance.

I can't say with 100% certainty on the back.