well if u are buying a LB that is out of car take a comp gauge, and a battery powered impact drill and what ever size socket for crank pulley and use impact to "turn" motor over and do like any other comp test

if the head is off then pull the pan if dark brown and skinks stay away bad maintenance done to it

tranny's look for gear oil in it take inner cv joint to stick in tranny and make sure they stay locked in and no bad bearings when u spin inner cv in the tranny

but best policy is to buy one u can test drive and be pulled in front u that day

hope it helps