What are the length of your pushrods? Maybe they are the wrong pushrods for a 440.
Does the rocker shaft have shims under it?
I'd be more interested in what the problem is, and then work on the best/cheapest way to correct it.
The ball-ball pushrods are available in almost any length you require.
Don't buy cheap roller rockers for a daily driver. Old school factory type adjustables - Cast Iron Ductile Mechanical Rocker Arm Package from Mopar Performance(P4120974) have been proven reliable for many years. The factory type adjustables use a cup-ball type pushrod, so you can add that to the price.