Looking for opinions.

As far as drivability goes, every slant I've had has ran great with 3.21, 3.55, or even 3.91 gears. The highway rpm was noticeably different, but the throttle response was so much better with the lower gearing. I imagine there were some 904 & 8-3/4 axle cars, but shortening your current drive shaft and using a conversion joint (if necessary) is probably your easiest option.