Aftermarket/Replacement Cylinder Head Rule Change

I think for stock the rules should be changed so any casting can be used as long as they have all the same volumes, valve sizes, and valve arrangements. We are there anyway why only allow some manufacturers and people to get replacement parts. Go to a SS cylinder head rule
for stock and be done with it. All the replacement head deal does is give select few racers an economic and performance advantage over the rest.
One more thing, all the guys crying that the new cars are not real stockers are wrong. They all have the parts they were designed with and run them.
How many original parts are in a 396/375? or a Plymouth 340 with aluminum heads and intake? Not many I’m sure. It’s getting stupid, nobody with a SBC can’t find parts?