I have a 1973 Ford F250 with a 351M and a C6 automatic. I just put in a new tranny... Since then my truck boggs down bad when accelerating, and after idling for a while a strong smell of raw gas comes, also, the tranny hangs up in the lower gears, but if you let off the gas it shifts. The truck did sit for about a year. Could all this come from a vacuum problem??? Maybe a timing problem? Or multiple problems??? The truck starts and idles fine..... It just falls on its ass something terrible.... Any Input would be greatly appreciated.......[COLOR=red]

It sounds like you're not getting vacuum to the modulator.Check that and report back.One fix at a time.