Might want to check this post too.
https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=834008#Post834008

Power piston stuck, power ball in wrong position (goes above spring), gasket blocking off vacuum passage to power piston (credit to pre '68 Dave), will all cause a very rich mixture off idle.


BC
1960 Chevy C10 driver 261 T5 4.10 dana 44 power loc
1949 GMC 250 project in waiting
1960 C60 pasture art
Retired GM dealer tech. 1980 - 2022