I read that the rocker shaft bolts are supposed to be torqued to 20lbs,just double tapping with moparts, is this correct?

(2) diff manuals show 15. 20 will not hurt you

200 inch pound

200/12 = ~17-18 ft lbs

That's right, doesn't take much to snap them off (and the '69 FSM for my 340 had the torque wrong (30 ft lbs, IIRC). I should have known a bolt that small couldn't take 30 ft. lbs.

E-berg sells a hardened version that is slightly longer also to allow another thread or three to bite deeper into the head.

Yeah a lot of places online state 30ft lbs. But I snapped one of the bolts that tight... and they are o ly grade 5, I bought grade 8 replacements. There a thread or two lo Ger so ill try 20lbs

best would be to go the recommended torque for a grade 8 bolt in that dia. You need the right amt (not too much not too little) of torque on the internal/external thread interface to get a certain amt of constant stretch/tension to hold the item (rocker arms) in place. Any manual should have a torque chart for std grade 8 bolts or ask at the place you purchase them. torque the shaft down level. I lightly hand tighten em till they touch and the shaft is perfectly horizontle then center 1/4 turn then near right 1/4 turn then near left of center 1/4 turn then far right 1/4 turn then far left 1/4 turn then back to center 1/4 turn & so on. Resist the urge to go more than 1/4 turn no matter how loose some are as the springs are compressed diff amts. You're goal is to draw the shaft down perfectly horizontle then when it's down bring all 5 up to the proper torque spec. Cleaned threads/lightly lubed w WD40 works for me and a straightened coat hanger horizontle to keep the pushrods lined up under the arms