Totally frustraded. Cant afford a mechanic. Need timing he

How do I find out the timing on a 1988 cheverolet c1500 4.3l v6?The motor I was told was pulled from a 1987 s-10. The distributor came with it.I tdc'ed the motor and have set the #1 plug wire at 6, 7, and 5 oclock positions. On 6 it wont fire at all, on 7 it will start but not time up correctly. It idles very roughly and carbons up the plugs. The best I could get was a lopsided lopeing at idle. If I pushed it up on rpms. It would run great. But I cant get a smooth idle. On 5 oclock it backfires thru the carb and starts fires.I am desperate and totally frustrated.I have beenon this for a week now and changed everything. Including the throttle body.I also changed the fuel filter. And yes I used a timing light. Lol