Wheel/Tire selection help please ?

We're getting ready to order some parts for the Duster and would appreciate some advice and any suggestions are more than welcome..

The car will be used mainly at the track, with a limited amount of street use. We don't want to re-locate the springs or cut anything if we can help it.

The engine will hopefully be pushing in the neighborhood of 375-400 hp, transmission is a 727 w/ reverse pattern floor shift. The rear end is a 3:91 suregrip, and the axles are the stock small bolt pattern -- 4" right?

We wanna go with MT ET street drag radials, and either weld or centerline rims, and convert to 15'. Here's where we need some help and suggestions..

What is the biggest rear tire/wheel combo we can run with the stock suspension, and what back spacing would we need? Also, what sized rim/tires do we wanna run up front?

As always, thanks in advance for any replies !!

Kenny