Whats needed to fit roller cam into my 1971 340?

I agree with what you're saying here for sure. I was wondering couldn't a custom cam be ground for the roller lifters? And at that point maybe having the cam Underground would help the lifters go down in the bourse? more for that oiling ring?
I think the reason everybody doesn't have a roller cam is because of the price right? I know our Durango does LOL
Yes, that cam undercut has been used as another solution; good catch. And yeah, the after market rollers are pricey. As long as the flat tappets cost 1/2 to 1/4 as much, they will stay in the mix.