Change 1-2 gears to lower ration gears 1967 Dart Automatic (904?)
have a look at this;
ignore the blue line.Ignore the right side numbers. Half all the other numbers.
This is now a visual representation of your 273 torque curve, up to 3000rpm.
Go to 3400(now 1700) and find the "torque" there on the red line, to be about 125 ftlbs@1700.
Go to 5600(now 2800) and find the torque there to be about 205 ftlbs@2800.
Now some math; your current first gear TM is 2.45x2.94=7.20.
And you are currently taking off at 7.2x 125ftlbs=900# road torque.
With a 2800TC, it would be 7.20 x 205=1476# road torque. This is a 64% improvement. And 1476 is just enough to initiate wheelspin.
If you had the 2.74 low gear and the stock TC, you would have 105x2.74x2.94=846#
It would take 1476/105=a 14.06 starter gear to equal what the TC can do. This would be 14.06/2.74=5.13 rear gears with the A998.
Ain't math grand. Even if the numbers are only approximate, you can clearly see the "approximate" results.
What I'm saying is; that to equal the take off power, of the 2800TC, and your current A904 with the 2.45 low in it, and your current 2.94s ..... would,
with the stock 1750TC, and the 2.74 low gear trans, still require; 5.13 rear gears!
But lets say you don't need that much take off performance. Ok lets look at a 2500TC. So you go to the 2500 rpm mark, which is 5000 on the chart, and follow that up to the red torque curve, and you will find about 200ftlbs@2500 there. And multiplying that by your current starter gear, we get 7.20x200=1440#, still enough to break traction, at least on the size I'm imagining that you are running, namely 255s or less.And finally, to equal 1440 with a 2.74low, and the current TC 125ftlbs would take ;
1440/(125x2.74)=4.20 rear gear.
The 2.94s will cruise at 65=2520@zeroslip (25.5tall tires), so the 2500 is a good match
have a look at this;
ignore the blue line.Ignore the right side numbers. Half all the other numbers.
This is now a visual representation of your 273 torque curve, up to 3000rpm.
Go to 3400(now 1700) and find the "torque" there on the red line, to be about 125 ftlbs@1700.
Go to 5600(now 2800) and find the torque there to be about 205 ftlbs@2800.
Now some math; your current first gear TM is 2.45x2.94=7.20.
And you are currently taking off at 7.2x 125ftlbs=900# road torque.
With a 2800TC, it would be 7.20 x 205=1476# road torque. This is a 64% improvement. And 1476 is just enough to initiate wheelspin.
If you had the 2.74 low gear and the stock TC, you would have 105x2.74x2.94=846#
It would take 1476/105=a 14.06 starter gear to equal what the TC can do. This would be 14.06/2.74=5.13 rear gears with the A998.
Ain't math grand. Even if the numbers are only approximate, you can clearly see the "approximate" results.
What I'm saying is; that to equal the take off power, of the 2800TC, and your current A904 with the 2.45 low in it, and your current 2.94s ..... would,
with the stock 1750TC, and the 2.74 low gear trans, still require; 5.13 rear gears!
But lets say you don't need that much take off performance. Ok lets look at a 2500TC. So you go to the 2500 rpm mark, which is 5000 on the chart, and follow that up to the red torque curve, and you will find about 200ftlbs@2500 there. And multiplying that by your current starter gear, we get 7.20x200=1440#, still enough to break traction, at least on the size I'm imagining that you are running, namely 255s or less.And finally, to equal 1440 with a 2.74low, and the current TC 125ftlbs would take ;
1440/(125x2.74)=4.20 rear gear.
The 2.94s will cruise at 65=2520@zeroslip (25.5tall tires), so the 2500 is a good match