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My Duster ran a best of 12.67 at 107 mph with a 1.9 sixty foot last summer. I want to optimize my combo during the off season. Currently the car has a 741 case with a broken Sure-Grip and 3.91 gear (Found out the Sure-Grip was broke at Milans all Mopar day. Embarrassing to say the least). I am definitely going to upgrade to a 742 case with a spool. I want to turn 6500 rpm through the traps and I run a 27" tall tire. I am thinking 4.30's will be good. You guys have never steered me wrong so I thought I would consult the experts before I made a move.

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Fix the posi first Once that is done make your decesion I would look at two third members, one for street and one for racing as far as the right ratio and finish line RPM find out where the car likes being shifted out of first and second gears by looking at the 330 and 660 ft. times and MPH Most stock lie SB like being shifted around 6300 to 6700 RPM, the steeper rear gears will help it some on the top end but they are not a cure all Maybe 9secondPhil will chime in on his fisrt "Cab" car and the results of changing the rear gears from 3:55 to 4:89, not much if I'm remembering correctly