My second car was a 1968 Dodge Charger (my favorite) with a 383, automatic and about a 2.50 rear end. I bought the car in March. Next morning the engine was frozen and busted. The asshole I bought it from drained the
antifreeze and put water in it without telling me. I found a 400 engine (two barrel carb) and put in it, so I never ran the 383.
The torque converter makes a tall gear much easier to tolerate. In drive, it shifted 1->2 at ~ 50 MPH and 2->3 ~ 90 MPH. If memory serves, it shifted around 5500 RPM. The 400 was out of breath at 6000.
It had decent tires, but an open differential. The tires would slip a little but it hooked to the ground very well. It would beet 289 Hi Po Mustangs and 400 Firebirds. Mostly because they were burning up tires and I was accelerating away.
I put a set of 440 heads, that was ported by a local racer, on it, with a monster cam, 1000 CFM carter, headers, etc. The engine made huge power above 4000 rpm and pulled strong all the way to 8000 rpm. It idle about 1500 rpm. What a horrible combination, but I was 17 yrs old and did it all myself. By the way at 8000 rpm 1->2 shift was 90 MPH and 2->3 was 135 MPH. It would peg a 150 MPH speedometer.
Now it had no power on take off, but when it hit about 40 MPH it would melt the tires. It was no fun to drive at all. I destroyed the transmision in about two weeks, and put it all back to normal. In hind sight, I wish I had tried leaving the heads on it, go to a milder cam, and change to a 3.5 rear end gear. At 17 I had built a half dozen engines, but had no idea how to work on a rear end.
The point to my little story is: don't design your engine to fit a rear end ratio. Build the engine you want and then put the correct gears in the rear end.
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