are the valves adjustableon a 78 model 300 6 cylinder?
or are the rocker nuts torqued to a determined torque value?

 

No those rocker arms are not adjustable. The predetermined factory torque setting is 25-30 ft lb's. as long as it is still stock without altering block, head, head gasket, or aftermarket rocker, such as rollers and stuff. Drop the pushrods, lifters , and rockers ontop. torque 25-30ft lb's and you are good to go my friend.

 

Are the lifters adjustable on a 2002 Ranger V6?