My AMX in D/S had 450#'s open pressure when it was running 10.50's. And I know some guys (multi-makes) running around 480#'s nowadays.
I shifted mine at 6800 RPM, not something I would call "extreme", went through the traps about the same.
Broke rockers all the time. Coated them, cryo'd them, ARP 7/16" studs (AMC is like a SBC rocker assembly) best fix was adjust valves every two to three runs. Guide plates & unlimited style valve spring were not legal at the time.
If I were doing it again I would try 7/16" dual taper pushrods with guide plates & a double (triple?) spring.
Some would say the cam profile was wrong. I don't know, had about a half-dozen in the car over the years, all custom grinds. Didn't break rockers too often until the spring pressures got up to 420. But then again the car got faster with the cam and springs.
Now when you look at it, NHRA will allow $1000 billet or tool steel cam cores, $800 Schubeck lifters (that may take out your engine) or tool steel lifters, they'll allow $600 push rods, they will allow beehive or ANY valve spring you want (neither allowed when I ran Stock) that can approach $500 a set, stainless valves, $750+ BBC 8.2L rockers with the whammy treatment and 1/2" rocker studs....but it would be ridiculous to allow $279 Crane Gold roller rockers that would live with the rest of the valve train!
