I just read 90% of the posted threads regarding valve adjustment on the 300 I-6 and it would appear that the general consensus is that you remove all of the lash until you cannot turn the pushrods with your finger and then tighten an additional 1/2 -3/4 turn. Presumably this adjustment occurs at TDC for each cylinder, correct? If this is the case, can I simply remove the rotor cap to find TDC for each cylinder and then adjust accordingly? Second question, if the stud nut is all the way down and the lash has not been removed, can I simply place a washer between the nut and the fulcrum seat? Last question, I would presume that the remaining valves would have to be adjusted at BDC. How can I quickly determine this? Thanks.

 

i have an 84 300 inline,i just replaced the head with a 77 300 head..just went though all that adjusting on it.
best way is to adjust each one on TDC..i only turned an extra 1/4 turn just to get it running..then adjusted them while running with the valve cover off..backed off the nut slowly untill it tapped..then tightened untill it stopped completely & then a 1/4 turn more..thats all id adjust on an older engine with old lifters..seemed if i tryed 1/2 or more it sputtered..opening the valve losing compression..if your lifters are older & somewhat wore out the 1/2 turn or more would cause loss of compression in that cylinder because the valve isnt sealing completely because the lifters arent as loaded as a newer one

you shouldnt have to use a washer to get them adjusted properly..there is plenty of threads on the studs for it..if thats the case..then your cam ,rockers..or valves are wasted

 

Dont get bogged down trying to get the chatter out of your valves by repeatedly trying to tighten them down (only to find out that the clearance keeps changing on you) Its lousy gummed up lifters that wont spring back up easily because of the gum/sludge, whatever. You need to try the Mystery oil remedy to try to clean out the moving parts of your engine, or possibly install all new lifters. Adjust the valves once, turning the engine to each valves correct position in the correct firing order and and tighten to the point where you cannot twirl your pushrods with your fingers (clearance removed), and then give another short turn (not more than 1/2 a turn). Go through them, and then try the Mystery oil. It will quickly clean out the gum and wont harm your engine. Replace a qt of oil with a qt of the Mystery oil. Run your truck gently a few days to try and loosen things up. Put 100 miles on it with the Mystery oil, and then put in fresh oil. It should improve and get quieter. Repeat this treatment in 4-5 weeks. It may save you from having to replace all your lifters. It worked for me.