Gentlemen;
These were on e-bay a few weeks back (Barker) & a lot of money as I recall.
These worked good back in the 50s & many used them cause it was easy to put them on, instead of changing the cam. The push rods would rub a little as Bryan mentioned but not 'bend' and they weren't "roller" rockers, just 'hi lift'.
There okay for stock but N/G with a 'cam' as the lift is to much & can cause the valve spring to collapse completly.
They were part of the "Hot Rod package" many did.
Milled head (.125), high lift rockers, 2 carb & headers with a hot coil too.
It would make a 85Hp 216" engine 140+/- and made money for the Accessory Houses
plus a lot of noise.