Would a 6th gear gimme much if an rpm drop when on the highway around 70-80?
http://www.latemodelrestoration.com/item/M7003M6266/Tremec-Magnum-T56-Transmission-M-7003-M6266
http://www.latemodelrestoration.com/item/M7003M6266/Tremec-Magnum-T56-Transmission-M-7003-M6266