I have a '76 highboy with a 390 4 speed but i was thinking about swapping out the tranny with a C6. The C6 is from a '83, I think. I do know it was a 351W. Would this mate up to my 390? Or possibly a 460 if I ever make a swap?

 

if the 83 had either a 351M, a 400, or another 460 then the C-6 should bolt right up to the 460... to bolt it to the 390 you'll need an adapter plate and they are expensive.. if the 83 had any engine other than those I already said, then you'll probably have the wrong bellhousing bolt pattern.......... You guys that know more than I do, please correct this if I'm wrong

 

X2...

FE engines have their own unique bellhousing bolt pattern

335/385 Series have their own (that would 351M/400/429/460)

Small blocks with Inline -6 cylinders

Y-Blocks

Flatheads yadda yadda yadda

For an FE C6 you'll have to source one from an FE, no other financially responsible way around it.

Josh