rocker adj. screw , how many threads

hi fellas, im trying to get a set of adjustable rocker arms set up on a 383. ive got some heads that have been milled .060 and when i put it all together the rocker adjuster screws dont have any threads showing . i think ive seen posts that say there should be at least 2 threads showing . if thats the case i guess im going to need shorter pushrods. anybody got any advice?