Transmissions that will bolt up to a 350

[81_Chevy]

ive got a 350 in my truck and am looking at a different transmission, possible a manual. i was wondering if anybody has done a 5 speed swap in our trucks? or possibly a 6 speed auto transmission from a newer chevy. it would be nice to have more speeds/ gears to get better MPG. any info is appreciated 

[Captkaos]

The NV4500 is a popular swap, not sure if there is anyone here that has done it though.  The newer trans like the 6 speed has to have a controller to make it shift.  They aren't cheap.

[Mario]

I recently finished installing a NV4500 in my '81 Silverado.  Advance Adapters has a bellhousing to utilize a manual clutch linkage.  Otherwise you could use a factory bellhousing with a slave cylinder, or a hydraulic throwout bearing.  The NP208 or 241 transfer cases bolt up directly.  The transmission mount requires zero drop with respect to the frame rails but is located at the position as a SM465.  I'm currently working on the floor cover in attempts of relocating the stock 208 shifter.  It drives pretty nice, and the shifting is smoother and faster.