273-318 rocker shaft differences

I'm not familiar enough with the 273 shafts to be positive, but I have read that you must use 273 shafts for them. I dont know if the Crane shafts will work with the factory arms, but I doubt it. If you are using the adjustable rockers ona hydraulic cam You may need to experiment a little to get the proload right. You're setting preload on the plunger, not lash, and there is a "sweet spot" where you'll quiet things down and not hurt the cam. If your heads have been worked, like a valve job or milling, then the amount of preload will be hard to find. The best way to find it is to pull the intake, and use a wire feeler gage to check the preload on each lifter. It'sa lot of work, but then you KNOW its right. I normally will adjust things to 1/2 turn tighter than the point where the pushrod cannot be twisted by your finger tips. If things are noisey, I'll re-adjust to 3/4 and see if things quiet down. I wont go tighter than that, because yo ucan wipe the cam easy. Also, you must be sure the engine is at running temperature when the valves are set. I do one side, then put the valve cover back on, and run the engne again, then go back and do the other side. Then it stays warm. Also, be SURE the cam is on the base circle (not any lift from the lobe) or you are doing it wrong, and can leave you way loose.