Distributor is in sync with TDC. Problem seems to have been solved by: (Entire valve train was all over map);#2 intake valve stud loose; #2 exhaust valve seated too low to seal (0.050 shim required under stud) -- adjusting took 2 1/4 turns to remove lash on exhaust and 2 turns on intake; other valves varied in seating up to 0.020. Studs are screw-in and don't enter the water jacket -- shims and other grinding on stud seats to get all valves in spec. Also found that EGR valve at 4 inches of vacuum immediately went wide open. That is the second EGR and have been told by countless shops that only OE EGR valves work properly. Replaced with Delco EGR valve. Running very stable and smooth. I thank all for the insight offered.
Now, I go to seek legal advise to go against rebuilder for not honoring warranty.
