If the heads havent been opened up , deep gasket match, then just drill them 9/16 and run it. Simple as that. It 90 bucks at rhe shop. Did this near same combo before.
'88 roller 360, used 974 casting heads from '74 . Runs a lunati. 585 hyd roller with mopar replacement rollers and spider.
All early casting heads need modifications to the push rod holes to run a roller cam.