Changing gears questions

txbullets said

Has a 904 in it now but putting a 727 with small stall in.

Building the car now. Car info
72 dart
68 340 10.5/1 comp.
X heads
Xe268 cam
Air Gapper intake
Have not bought a carb yet but 750 dp most likely
Dougs headers

Would like to run mid to high 12s but not stressing that. Mostly a street car with occasional trip to the track for fun.

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Why are you changing the trans to something that'll make it slower and use more fuel? Don't get me wrong I love the 727 but it's a power hog and generally not needed with a stock stroke small block. 12's should be no problem as long as you get it to hook good.

As for gears keep this in mind. The rear tire ht has an effect on the final drive ratio. If your running short tires (26-1/2" or less) run the 3.55 gear. If your running taller tires (27" and up) run the 3.73's