1972 Demon 340 engine mods

Any of you guys have experience with using stamped rockers and stock pushrods with iron to edelbrock rpm heads swap? I am tempted to do just this first but not sure if I need any different pushrods?
I'm tempted to get the heads off, swap it all but camshaft, use stock rockers, lifters and cam to get my measurements before we order the cam that it needs. I hate this guessing game.
Also wanted the car to be running in the mean time. I need to wait about a month for parts to get here.

Another factor is my SHITY cheap cylinder pressure gauge that I just use to see if all cylinders check the same and don't really trust what it shows.