Jim I was running a 315/60 drag radial approx. 30" tall. I recently switched to 31x16.5 QTP that are 31" tall and will have some growth. I should trap at 7300 rpms in the 1/4. my 496" set up was a street/strip combo; pump gas and I used nitrous at the track so the 4.10 worked well. Now I am going to run all motor with a taller tire and the 4.56 seems to be best for wringing everything out of this combo.