700R4 3&4 slip

[JND]

i have a 700r4 trans it is about 3-4 years old, isince i installed twin turbo sbc setup, since i matted the pedal on the highway i have been having some issues with 3rd and 4th holding. 1st 2nd and all shifts are nice and tight and hard. when in 3rd and 4th and getting into the pedal the rpm will increase but not the MPH, you could feel the slip, if you ease into the pedal it seems okay.. i have read that this could be a 3&4 clutch pack issue.. should my oil be burt looking and or smell? i am running a hydraulic lockup, could this be a converter issue? just want to explore my options... are 200r4 transmisions better? stronger? not sure if it is worth repairing the 700 or having a 200 built.
i want to keep the OD, i may also conside a manual trans swap what would be the best manual tranny for a sbc.

thanks for any advise/ideas

Joe

[XcYZ]

Jody has some experience with a high hp motor in front of a 200. Maybe he will chime in.