The flywheel from the straight 6 is on the 305 but it seems to be to big because the starter won't fit? The flywheel &the TQ converter are original to the L6 w/TH350. The 305 had a M/T, so I can't use those parts. Do I need a smaller flywheel or a different starter?

You need a 305 flexplate. A manual has a fly wheel, an auto has a flexplate (that tid bit will help at the parts store!!! :) ) Also if you use the wrong flexplate the crank will be off balance and it will waller everything out. Also you need a 305 starter not a L6

Everywhere I've looked gives me the same part number for the flexplate on both the 305 & the L6!!!
I have the 305 starter but it doesn't fit!