It's not the material as much as the designs. T&D will take MUCH more spring pressure and abuse than any Crane or Harland Sharp. There's no reason to worry about running the right aluminum rocker on the street. These cars are not running 360 days a year and racking you 20K a year. If the spring keeps the valve and lifter under control, you will not have an issue. The last 505 runs an Engle cam, but Comp springs because IMO Engle didnt want enough spring in it. I prefer to run a little much than just enough or not enough on a street car. Because like detonation, it's bad harmonics that break rockers, retainers, and locks. On Edelbrock heads now shipped as assemblies the springs are barely adequate for older street profiles, never mind a modern grind. I know of many street car solid roller cam engines that run T&Ds on thier heads that are years old. Even with rebuilding the roller lifters and replacing the valve springs as required. The design and materials are much better than the budget lines.
