I want to do some 15 x 10 or larger on the rear of my 97Z.

Can this be done?

Of course I want to keep it under the 1/4 Panel.

 

Not sure.... stuff like offset beco,e critical when pushing the limits ... are you trying this for a slick? Its the only reason to go down in rim size
Dont run slicks on the stock rearend...carnage will ensue...very weak

 

Slicks on the street? LOL, seriously, what is the biggest rim i can get under there?

 

i have 19 inch z06 rims on my rear 285 which is 11.22 inches wide some guys go 305 which is 12 inch wide but you have to trim your fenders on the inside unless you do like me and use air shocks to keep the fender from coming down onto the tire when you go over a bump

 

What is the back spacing?

 

The stock 4th Gen wheels are 16x8, with a 55mm offset. That produces roughly a 6.65" backspace.

The stock 4th Gen wheels on athe WS6 and SS are 17x9, with a 55mm offset. That produced roughly a 7.15" backspace.

The best size for a 4th Gen, IMHO is the 17x9.5", available in a lot of places because the Corvettes used a 17x9.5" wheel. You can get "ZR1" replicas in this size for example, Torque Thrust II's, various years of Corvette wheels.

For a 17x9 or a 17x9.5" wheel, you can handle a maximum backspace of about 7.40" in the front. The ZR1 replica with a 56mm offset has that dimension and fits correctly. I can post pic's of them if you want.

You could also go as low as a 7.00" backspace on a 17x9.5" wheel. I believe that is the standard dimension recommended by ARE for the TT-II's for the 4th Gen. That is about a 45mm offset.

In the back, you can use as large as a 7.93" backspace, which corresponds to the ZR1 replica with the GS offset - 50mm, on a 17x11 wheel. That will require some inner fender massaging though.