I picked up a 63 390 galaxie 3 speed toploader for $25, a bellhousing & a pedal from a 400m bronco for $15, a flywheel from a 390 for $20, and a shifter for $15, out of craigs list, ebay, local junk yards, etc. I bought a new clutch/pp/to bearing from napa. It's all going in soon. I gotta build a z bar and brackets, and set it all up.
You should put my c6 behind your engine. It's been slipping and dying for 7 years. At one point 5 years ago, it was slipping so bad that I couldn't leave the neighborhood. I put 1/4 cup of brake fluid in it and its been going ever since. It's been flaring pretty bad going into 3rd for 2 years. I just ease off of it to let it shift. I don't baby it otherwise.