I dug out my accelerator pedal pushrod ('51 3100 216 with Carter carb). It measures 17" from center of pedal hole to the crank pin. It does have some offsets and bends, but it NOT adjustable (without bending). There's a stop on the toeboard that the pedal hits before it would contact a floor mat and/or padding (unless that's really thick.) I believe that stop is 1-1/2" tall. I measured it once for a 'bolter who needed to fab one. That stop could be shortened if you have a problem at the carb. I don't think there was an issue with throttle travel at the carb, although I can't be sure as I haven't had it on the road yet.
Here's the post with pedal pivot and stop dimensions.
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