89 s-10 won't start

My brother-in-law has an 89 s-10 4.3l v-6 that he rebuilt. After rebuiling it ran like a dream but had no oil pressure.Come to find out when he had the block dipped the shop knocked out two oil plugs that he knew nothing about. So he pulled the block and put oil plugs in and also had to replace throttle body because he busted it putting the fuel line back in. He then tried to start it and couldn't get it to start so his uncle to a look at it and he had mixed the wires up on the back of the distributor. He then had to adjust the valves because he had messed with them prior to his uncle looking at it. He got it to start but it was running really bad. Once it would idle down it would cut off but you could a rocker arm tapping like it was really loose so i took all the lash out of it and it would not start again. At this point i decided it would be best to go back through the valves again according to the chilton manual. Still no start it spins over and sounds like its going to start but doesn't. At this point i am puzzled and don't know what to do because i never had problems like this out of my 91 s-10 blazer that i rebuilt. Please someone help this truck needs to run.
Thanks in advance

How long was it run without oil pressure?
I would start with rechecking the valve adjustment.
Make sure they are not to tight and run a compression check on it to start with.

i got a 91 s-10 and mine would't start 1 day ijust turned it off and never started again i replaced coil and module still wouldn't start then i took out distrbiter found it had a crack in it put new 1 in started right up..is it getting spark to the plugs??? if not it's not going to start but i know you know that. good luck...

scrapper....

i also meant to tell you that he changed the starter but used one off an early 80's model jimmy which was bigger that the one that came off his truck. When trying to crank it from time to time it sounds like the starter is trying to hang because the speed that it is spinning the motor gets sluggish or even has stopped.

You might need to check your timing also. after a rebuild and with the amount of work being performed around the distributor, one tooth off could make it run like crap.

I also just put a starter in my 89 s-15. needed a " gear reduction " starter. Two different starters came with that year. Your starter is probably drawing too many amps so it will sound like it is dragging.