See if you can find a 93-96 F body T56. 6 speeds. Standard gen 1 SBC bellhousing. 1-4 is a regular muscle car box. 4th is 1-1. 5th is an around town OD (0.7 on the 94-96), and 6th is a great highway cruising 0.5 that allows you to run some serious gears out back. I have this trans in my Impala SS, combined with 4.10s. Amazing acceleration, barely over 2000rpm at 65mph. Also, the 94-6 version is rated at 450ft-lbs. Hydraulic clutch, so no worries about the linkage. You can get it brand new, or rebuilt if you want, and then you can order the ratios you want, too. I went with used, and it has been fine for 15 years.
Two doors, four doors, wagons, and ragtops.