[PxTx]

I'm surprised Eric has not commented yet. Ensuring proper valvetrain geometry can be more complicated that most of us would like. Though a competent mechanic can swap rocker arms- the ones in capable of properly checking everything are s small minority.

I trust you'll be able to install the stock type valve covers, but how easy or how much it will cost is a tough answer to give with the information provided.

My sister's Nova has a set of Crower Stainless Steel roller rockers. I would not be surprised if they would fit under a stock set of covers with a thick gasket. FYI, should your you have issues with the slot on stock rocker arms.