checking pushrod length

He's already got a checker. Chuck it in there with 273 rockers, crank down the adjuster to show 1-2 threads under rocker and then adjust the checker to depress the plunger .090 into the lifter to set your preload for Hughes cam and iron/AL combo. .090 is almost 2 turns of a rocker adjuster. So you can loosen the rocker 2 turns (from 1.5-2 threads showing) and then you adjust to get checker to touch lifter then crank the adjuster 1.8 turn in. Now your at .090 preload with your 1.5-2 threads showing. Measure the checker for the correct pushrod length and order. you can do the same with the stamped rockers, you just need to add the preload to the adjustable pushrod checker. Careful how you order ball and cup. Sometimes they say end to end, sometimes its end to cup seat.