All I can tell you is I run 30 x 9 Hoosier radial slicks with 4.30's. I drive on the street all the time like this also. I like the combo for my 493 wedge which has Indy EZ heads and uses a flat tappet solid of 264 and 270 @ .050 with .630 and .634 lift with 1.6 rockers. It is a 493 as it has the 4.15 crank. I use a Dynamic 9.5 converter and have only made 2 passes so far with 11.04 @ 121 best so far. I know it has alot more in it as it was very lean that day. I shift about 6 and trap about 6200 and I may even gear down as I dont think I need so much gear with the torque of this compared to my old 440. I dont know how much your Hemi will like the RPM but with the cubes and torque you have I dont think I would go to a shorter tire. But like I say I have never raced a Hemi so maybe you might try a tad shorter and see if the car likes it. Ron