Going with more gear will no always make a car faster. Example, one of my buddies I race with every week was running mid 6.30's in the 1/8 with 1.38 avg 60' times. He was running a 5.83 gear. He decided he wanted to go 1/4 racing so he took the .83's out and installed a 5.13. The car ran the exact same et, with the same 60' and actually ran 1 mph more. If the car has too much gear, it will accelerate out of its powerband too quickly and not use the HP to move the car. I run a 4.86 in my car using a 4v cleveland. No way would I ever dream about putting anything more than a 5.14 in it, and only then if I were to put a taller (like a 33") tire on it. It would slow the car down. 1/8 mile it goes thru the lights about 64-6500 around 107 mph, 1/4 it goes thru about 72-7300 around 132 mph. If the convertor matches the combo, the same gear will be perfect for either length of racing.