cummins 250 truck motor over head adjustment procedure issues (HELP)

Hey guys, ive done several inframes over the yrs on 855 s an it seems as evertime when I start running the over head procedure the motor tends to lock down, its allways locking the motor down an cant turn it over by hand, im constantly having to try backing off the valves an injectors ,, it seems eventually after screwing around with it for an hr or so, finally it will all adjust like its suppose too,,,, so now ive done an inframe on an 1974 gmc white dump truck an it has an cummins 250 in it. never seen one like this, its heads seem to bolt on sideways an not flat like normal. so when I started running the over head using the accessory drive marks I started out using the (A mark) an found witch valves were loose. so I adjusted the valves on number 2 valve an set the injector on the number 4 cylinder. an then I tried turning the motor over to the B setting mark, but then the motor locked down before I got there.

marks injector valve

A 3 5
B 6 3
C 2 6
A 4 2
B 1 4
C 5 1

IM HOPEING IM USEING THE CORRECT ORDER FOR OVER HEAD PROCEDURE, I LOOKED IT UP FOR A 855

cummins 250 truck motor over head adjustment procedure issues (HELP)