In 1984 the trans would have been a 350C which
is a 350 trans with a lockup converter. The input
shaft on the 350C is longer to supply oil to the
lockup clutch. The 350C converter will not work
with a 400 trans. From the info I've seen the switch pitch converters were not an option in Chevy models. The converters from a 350 or 400
are interchangeable.
Arnie
