200-R4 transmission behind mopar stroker

All the reading I've been doing tells me that I should go with a 4l80. I know I will have to modify the tunnel, but I can run a forward valve body and get away from the elect, use the wilcap adapter plate, and have a lock up billet converter made with any stall up to 5200. Pictures I have show that with the 4l80 I'll need some major tunnel mods including possibly shifting my gas pedal over 1-2" b/c of the hump.. not really a big deal. the TC would lock up with a switch of a button, and the OD is .74 I believe. This set up would cost me less than having my 727 rebuilt $700, new TC $800, GV $2600.. the GM tranny with all the stuff I need is $3300