Please help me clear my head on what is needed for a SBC T56 Swap.

[Y-TRY]

I chose the TKO over a 6-speed also.

I had 3.89's with my 5-speed and highway driving was very comfortable with one overdrive. But final drive wasn't an issue, it was 1st gear. The 5 and 6 speed transmissions share the same 1st gear: 3.27:1. After my first drive I immediately yanked the 3.89's and swapped in 3.25's.

Frankly, the combination of a 3.27 1st gear and 3.89 rear gears is bad. Read my "Driving Impressions" thread. With the engine you speak of you won't need the torque mulitplication of a steep gear, anyway. So why suffer with an ultra-granny first gear?

IMHO, putting in a rear gear that matches the 3.27 first gear would result in a 6th gear cruise rpm just above idle, and that's just no fun.