I'm likely leaving a little bit on the table, I run a 4.10 with a 33" tire. 3000#, 850 hp. I stayed with the 4.10 since I hope to hit it with a little spray in the future. It's done a best of 1.25 sixty but more typical is 1.28 or 1.29 I took out 4.56's when I put in the new motor so I never tried it with any other gear. I have no suggestions since I've never tried any other gear, just providing info as a point of reference.