4BT all the way, in my opinion, you will always get mixed opinions on this subject, but I love mine!
Jeep 1:Used to have a 93 YJ 2.5l- 3.5" Black Diamond, Chevy TBI 5.7l V8, SM 465 4 speed, 8.8 rear( 4.10, L/S), rhinoline, Mile Marker 9000, NP 231, Had to sell it due to college
Jeep 2: 89/91 YJ, 4BT Cummins, NV4500, NP 231, Old Man Emu 2.5" suspension lift, 1" body lift.....Runs and drives, but very much a project
Interned at Novak Conversions 2 summers ago
Ask me about my 4BT Cummins Motor Mounts!!