I wouldn’t waste the time and money on a flat tappet camshaft.
It might not happen immediately, but It will fail on you. When Zinc was removed from engine oil, flat tappet cams became endangered species. You can add zinc back as an aftermarket pour in, but it isn’t the same. Cams are still failing. And when that happens, the rest of the engine will be just as dead as the flat cam.
I’m so convinced of this that I paid stupid money to have a custom roller ground for an engine that cannot have a roller in it as built by the factory.
And I made it fit.
But you don’t have to do none of that...
All you have to do is buy a set of link bar roller lifters, and the commensurate roller cam. And use regular oil, and never look back.
Or put a flat tappet cam in it, And wait.