I just put these on front look pretty good 15 x 8 inch US Mag Ramblers u111 with 245 60 15s. I also installed some 12 inch brakes from Stoptech and Wilwood. Basically the Wilwood D52 dual piston caliper and the Stoptech 12 inch 1989 trans am rotor 1 LE package (drilled and slotted). I already had the 1978 12 inch Impala spindles. I pressed out the 12mm studs and put in 1/2 inch ones to match the back. They clear the rims fine. I am working on rears now (via Weldcraft) which will be about 15 x 9.5 inches with a 6 inch back spacing with 295 50 15s and adding the Wilwood 11 inch rear disc brake stuff.
Car sits a little high as it just came off the jack stands.