Well, I have been working on the my Unlimited 91 Suburban build up!!! So far I have Dana 60 with 5.13's, Yukon 35 spine inner and outer axles new kingpens, OX U-Joints, ARB and ORD cross over steering, spindle seal kit wheel bearings and single wheel bearing hub's and rotors, all new parts and the same for the 14FF ARB and 5.13 with TSM rear calipers with parking brake's S/S brake lines. BDS 8" springs and a 3" body lift with poly bushings. ORD steering brace and greasable suspension bushins all the way around 1" zero rate add a leaves. Heavy duty front shackles and a lot of other parts.. NOW, the motor Is a GM marine HP3 with over 600hp and 600ft-lbs of torque, GM has been working with me hand and hand on this motor. PCM (computer) with harness, custom programming, TAC module and electronic pedal are from Speartech out of Anderson, Indiana. Ok, I am still try to make up my mind on the Trans. I am running an ORD gen2 doubler. Would like to run an Allison but do not have any experience with one. Is the output shaft 32 spline and the proper diameter? If so can you just re-drill the face of the NP-203 and bolt the case directly to the tranny and plug the existing holes to prevent oil leaks. Or do you need an adapter to mount the np203. Thank you for you time, Matt!!!