No real need for an aftermarket converter when the 10.75" Chrysler converter was on lots of OEM production vehicles, including my '70 383/330 Monaco. In the Chrysler Reman catalog, it also used to be spec'd for '68 Road Runner 383/335 and slant 6s. Probably many 440/375 cars, too. Seems like it was also referred to as "Street HEMI" converter, too?
KEY thing is that it loads the engine less at idle and lets the engine rev free'r until it gets tighter. Stall speeds are tossed around a bit too much, by observation. A converter that stalls at 1800rpm behind a 383-2bbl will stall higher when its behind a 440/350, just because there's more power in front of the converter. Conversely, a converter that stalls at 2800rpm behind a 440 will stall at lower rpms when behind a 383-2bbl.
Additionally, if you read the factory-spec stall speeds in the 1978 Chrylser service manual, you'd suspect they were building race motors although the stock motors (400s and 440s) were low-compression motors. Many were in the 2800-3000rpm range! From the factory!
Unless you need that TCI or Hughes decal on the car for contingency money if you win at the drag strip, I suspect that a quality reman unit could do just as well, if you get the one for the correct OEM application. Which could be "Street HEMI", considering the camshaft you have. Whether you need the balance weights on the converter or not will depend upon what's in the motor that can make it "internal" or "external" balance.
Just some thoughts,
CBODY67
