Have a 69 Dart, currently stock 5.9 with fuel injection, 833 4spd , 8.75 3.23 sg.. Best time so far is 14.3,would like to get into the 13's and think I can with some lower gears.Eventually going to do a cam, tune and a few other engine upgrades. Only go to the track a couple times a year, otherwise just an around town cruiser, doesn't see the highway. I have a spare chuck with 3.23 for street use. What gears would be best for my setup 3.91 or 4.10 or would I even notice a difference between the two?