I have a 1990 with a 2.5, took it on a trade with out hearing it run. Even with a few problems I still made out on the deal. When I start it, it runes fine, but it knocks, sounds like in the bottom end so I pulled the oil pan and put a set of rod and main bearings in it. The mains are .010 under and the rods are .030 under. Also put a timing set and tensioner in it. Airlock sounds the same, like a diesel. Any suggestions on where I should be looking next?