Ken:
I will have to run some calculations for you based on 35" tires.
The 5.13's do not necessarily work better than the 4.88's when running on the 1/4.
The idea is to be still within the power band when crossing the finish in 3rd gear WITHOUT having the third shift to OD. The GM trans has a wide band of gears and going into OD should be avoided, if possible. It is bad enough working from 1st to 3rd because of the jump in ratio between each gear change.
GM had to widen the band from 1st gear to OD to help meet EPA mininmum fleet gas mileage requirements. In the 70's, you had three gears to get to 1:1 and it made a big diff in getting down the 1/4. Now, we only have two so with each shift, the engine has to start lower in the band--therefor robbing power.
I was working on a better transmission gear combination when I got wrapped up with the WoO. For now my 1/4 mile work is on hold--hopefully not for long. Getting my 3rd and 4th H2s will take a while as my sponsors unfold. I will keep one for 1/4 mile fun!
I will need to calculate a theoretical MPH at the end of the 1/4 to make sure you are not outrunning your tire size---i.e. you do not want to be maxed out prior to the end of the 1/4 when in 3rd gear.
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