High altitude timming 94 GMC w engine 4.3

I think I fixed the code 44 while towing. I found my pvc leaking. The hoses and the PCV valve was bad. A bolt was missing from the intake
cover...I replaced it and retorked the whole intake.... the idel dropped abot 100 rpm....so must have been a leak or two. New fuel filter (shit should have read the box got sprayed in the face with gas) Any ways I know the timming was never set with a light before....(cant won't esplain) but what I did was advance it one degree at a time about 3 or 4 total and gunned it with the AC on untill I got what I thought was the best response off the line. Just wondering if by fluke I am closer to spec or just needed a slight advance because of my higher altitude or it was just to retarded in the first place also prolly a worn cam chain etc...and may never run at spec. Does this old trick still work on the newer engines has any one done this??? Seems to run as good as new....I was just wondering.
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