Al, I knew the basic gearing laws but now reading this post it's brought up a few questions. Case in point. I went from 4.10 to 4.56 gear. Went to Tune Tec and had the car dynoed. My hp/tq levels basically stated the same. But when I went to the track my mph did suffer about 1-3 mph. Now I thought bigger gears would yield higher mph due to the gears help put the engine in it's powerband quicker and longer during the run. But yes my 60ft and 1/8 times are faster(et wise)but the mph is alittle lower. So your saying that if I were to 4.10's back in I would gain the mph but lose the et. I understand that, but wouldn't a higher mph offset(well almost) for slower acceleration? Or would it be better to go with a larger diameter tire than opposed to a lower gear ratio? -Mark