"Fun" with adjustable rockers and hydraulic lifters

You need shorter pushrods than the stock 273 solid pushrods, ones intended for a hydraulic flat tappet lifter and adjustable rockers. Crane, comp etc sells them in sets. If in doubt check their websites for the dimensions and measure what you have to figure out if what you have is correct.

Once you get the right set up, you set the preload in the following way: Bring each valve around to its heel (0 lift). Using the adjuster, take the slack out of the pushrod until it just goes away. Then you need .020 to .060" preload. Since your adjusters have 24 threads per inch, one turn on the adjuster = 1/24 of an inch or about .041", turn them in one full turn and set the lock nut, no more than 20-25 ft lbs torque (dont ask me why I know). repeat for each valve until completed.

If you still have the friction adjusters I recommend replacing them with the lock nut style, which again crane, mopar etc sell.