timing / distributor problems

O.K. I have a 1988 Jeep Cherokee with a 1996 4.0 engine. The mounting tab for my distributor and I had a major oil leak so it was time to replace the distributor. Heres the problem, i have to use the 88 distributor to match the wiring harness that I have as the 96 distributor has a different hookup. The 88 distributor is not really adjustable and the 96 has pins in the bottom to let you adjust the timing which is needed for the 96 engine but I dont have that and had to just move the distributor tooth by tooth and get it to a point were it runs pretty good but it still isnt perfect. How do I adjust my timing in this scenario? I took it to a mechanic and he couldnt really figure this out either and I was hoping that you all could help me. The configuration that seems to work best is when the pickup is at just past 11 oclock and the button pointing at 5 oclock. When I use the timing light it shows that it is off on the timing by 30-40 degrees but when I set it to where the timing should be perfect the engine backfires really badly or doesnt run at all. If anybody can give me ideas to try or knows whats up please help.

Your timing is not adjustable. It is not controlled by the distributor, but by the crank position sensor (CKP) (aka CPS). Get the balancer marks lines up with the timing marks. Then make sure that the rotor is pointed at the #1 cyl tower in the distributor. If you are 180 degrees (1/2 turn), turn the engine around one more time to get the rotor closer to the #1 tower. Pop up the dist and move it one tooth at a time until you get the best line up between the cap and rotor.

Whoops, popped it twice.

When I do all that, which I have done, it runs really bad and backfires every time I push the gas. When I pull the distributor and move it two teeth in one direction it runs a lot better but still backfires some under full throttle and a mechanic frind of mine says the timing is still not right. If i move it another tooth it doesnt even start and if I move it in the other direction things get worse in that direction to.