Billy has a very good point about SLR, I switch low gear ratio in my old M.W. stocker in 1988 for the NHRA World finals at Pomona in 1988, took out the stock 2.45 low gear ratio and put in the Mopar brand 2.77 low gear (2.45X4.89=11.98) and swapped the third member from the 4.89 ratio to 4.56 which = 12.63 SLR
That made the car quicker and faster than it had ran that year
If you don't test you don't learn