Evening all,
I need some advice. My Charger came with no drivetrain and I'm currently piecing one together. I found a 383 out of a 68 Charger (score!) and it came with an 11 3/4 flexplate. I then found a 727 out of a 68 imperial that had a high stall converter. Takes a 10 3/4 flexplate and also has a wide ring gear. I'm trying to pick a torque converter and Monster is asking whether I want a narrow (1/2") or wide (1") ring gear. I'm not sure whether I should copy what the transmission came with or what the engine would have come with. Does it matter? Any advise would be greatly appreciated. Thanks!
Converter selection depends on some other factors. Will the engine be HP or standard performance? What will the axle ratio be?
If the engine will be standard performance with a low numeric ratio rear end, the 11 3/4" (narrow ring gear) would be a better choice.
I had a 1978 Trail Duster, original 440 and the transmission had been replaced before I bought it, It had 32" tires and 3.21 gears. The transmission shop put a 10 3/4" converter in it and the truck was a slug. It was s-l-o-w. The transmission slipped too much due to the converter size and tall axle gearing.
Conversely, my 75 Power Wagon 440 has an 11 3/4" converter and 4.10 gears. It is snappy and performs well.\
A stock engine does not need, nor will it benefit from a higher stall converter.
Maybe your high stall from that Imperial was another mistake made by a transmission shop. Imperials did not have high performance engines, their engines were tuned for low to midrange power.
Trucks and vans are a great source for these 11 3/4" converters. One from a small block 727 will still work as long as it is NOT a lockup type converter.
Thanks for the responses guys. I ended up not using the Imperial transmission. We got it opened up and the internals were just gone. More rust than metal. Ended up rebuilding a good 727 core out of a 73 D100. Sat down with my transmission builder and we contacted Hughes performance with all my specs. Settled on a 2200-2500 stall converter. Should be nice and snappy but still a good street car. fingers crossed.