Your chain is now in an unnatural situation. The tensioner takes up slack on the right. Check the marks on the both cams' thrust washers against the marks on the towers with #1 at TDC on the crank. Then put the tensioner in and crank the engine a couple of times to pressurize it, and recheck. You should be very close unless your chain has a lot of stretch.
What happened to your adventure with the tensioner rail plug?
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe