A833 4 Speed Problems.

i had a similar issue with a 4spd. and it turned out to be a bad clutch fork where it held the throwout bearing (some how 1 end of the clip 0n the fork broke), causing it to not release the clutch fully. i could drive and change gears sometimes reverse would grind but clutch just didnt feel right.

I was using a 10.95 440 pressure plate and clutch to hold a 273 in a 64 Barracuda. All kinds flexing going on!! Broke a Z bar at the tube and adjusting rods every once in a while. Sounds like something is flexing or out of spec. Just because the clutch is new, does not mean it is good. I'd take the whole car back to the guy who did the tranny and get his opinion.