Hi Max,Yes I set timing with vacuum disconnected,and underhood decal says to plug vacuum at EGR valve.Is there a way to check that EGR valve is working properly? Can it be removed from the intake and lubercated to make sure it is not froze up? It has been awhile that I had the pleasure to work on something this old.Had to dig up alot of old shop manuals that I saved over the years!!. Do you think that it could also be alot of carbon built up on the pistons??.Or do you think it could be the timing chain and gears?Hope to here back from you....Diesel1962