The 216 has a 3 3/4" stroke, and the 235 bumps that up to 3 15/16". That's a lot of leverage on the trans input shaft, particularly when the compression ratio was increased on the 56-up 235's. Since the cylinder head port geometry restricts airflow pretty severely and porting and polishing doesn't help much to get the RPM up, all we're left to work with is torque. Going to the slightly oversized intake valves used on the early Powerglide engines, and using an 848 head with a little more head milling will help a little, but it's expensive, and requires some pretty involved machine work. Too much cam and/or carburetion actually reduces low-end torque, so the 2-carb setup with a lumpy camshaft makes the engine look and sound good, but it's wasted effort. Dual exhausts without the multiple carburetion can be helpful, however.
The same concept was used by Ford for a long time, with a 3 3/4" stroke on their V8's for almost 30 years, and a 4" stroke in the 49-53 Mercury engine. The Mercury crankshaft was a welcome change for the hotrodders- - - -it fit in the Ford blocks, and with some offset grinding and welding, the stroke could be increased to 4 1/4" without a great deal of effort. 4 1/8" was possible without welding, by using the small-diameter connecting rods that were used in the 85 HP V8's from the late 1930's. The round track engines my father ran in the early 1950's had a 3 7/16" bore (1/4" oversize) and a 4 1/8" stroke, with 11:1 compression and alcohol. Then he turned them up to about 6K RPM with only 3 main bearings! When one scattered, it really hand-grenaded!
Jerry
