Alan,
I did a conversion a couple of months ago for a fellow Stovebolter. We installed a Goodwrench 350 and used the original transmission. I made up a spreadsheet with all the parts and costs. If this would be of some use to you, send me an email and I'll send it to you.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine