I'm using the 1950 216 bellhousing, starter, and 4 speed transmission on my '62 261. I am also using the 261's flywheel and 11" clutch. I had the flywheel turned down to fit the 216 ring gear so I could use the footstomp starter. You can use the 216 flywheel on the 261 but I had one with a 9" clutch which will not hold up well on a 261 in a truck. It all bolts up very nicely. The clutch is a tight fit in the bellhousing but it all works fine.
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1950 Chevy pickup with '62 261, 4 speed.