roy that video is how mine used to do and now it dont .. i even tried to suck on the metal line at the carb tring to get it to advanve and it didnt , i did a check on the metal line and no leaks so that tells me that the diaphragm ius bad ( no? ) i will try hooking my guage up the metal line that goes to the vacuum adavanve and see if the carb is pulling , what should it be when revving up , i guess it should bounce up and come down when the engine come down ??

thanks guys

1958 chevy biscayne
235 6 cyl 1 barrel
2 speed PG tranny