u dont need to swap anthing…just move the mounting hole for the trans mount back or forward (i forgot) a 1/2 inch and then u need to decide if u want a floor shifter or not…its easier to do a floor shifter i think…everything clears and bolts right up…if u dont live far away just hit me up when u are doing the swap…we can easily do it in one day…u will need to re program ur computer since the th400 isnt controlled by the computer.
the 4l80e is a good tranny but u are in the same boat cost wise…
the th400 doesnt have a great frist gear but i’m able to get 1.7 60ft times no problem with slicks and 3500 stall on a stock motor…the th350 will have more options for first gear