There's a new option on the market for 6 speed conversions using the Nissan transmission. The kit seems pricey, but the transmissions are cheap, making your all in conversion much more affordable than a T-56 swap. I'm curious how well these transmissions would fit in the tunnel of an A-body. A quick internet search revealed some used transmissions as low as $650.
To me, the whole reason to go through the hassle and expense of installing a six speed trans would be so I could run a 4.11-4.30 rear gear comfortably.
