I have been doing measurments for a 302 Ford, it ooks like it will fit (if you get one in a Miata it should fit in a Sportage) so I'm sure you could get a 4.3 in one. There is one on utube with a 454. The stock Getdrag trans is capable of handling about 250 HP, I am not sure about the t-case. If you look a Dave Scott's 95 he has Dana 44s with 38s. 44s will be huge on a Sportage (cool) but may be much for Toyota axles.

Dennis

95 Sportage, gone but not forgotten.
98 Jeep TJ, 4" Zone springs with RC Long arms, Ford 8.8", 4.56 gears & Detroit locker rear, D30, 4.56 & Detroit Trutrack front.