Jerry, I don't understand what you're referring to. Of course we're all talking about roller cams here, where spring pressures are much, higher and ramps are much steeper. Some solid roller cams only have 28° between .050" duration and seat duration. That's open the valve REAL quick, holding it open for a long time, then slamming it down. Running a hydraulic lifter on that ramp with enough spring pressure to keep the valves from floating at high revs would probably collapse the lifter.
Berm, I don't know why a cam designer would recommend such wimpy springs on such a thumpy cam. If I remember your specs from the other thread, it's not exactly a street roller cam. The only caveat would be if he recommended a specific install height with those springs. You can take a 400lb spring and shim it enough to get 450lbs out of it, you know what I mean?
On a solid roller, I would never go under 250lbs seat and 500 lbs open and I wouldn't care to run a lot more than that on a billet core.
For a hydraulic roller, I usually aim for about 130-140lbs seat and 325-350 lbs open, depending on the grind.
Comp Cams Endure-X lifters are engineered for street use, yes. They are pressure fed lifters. There are better choices out there, but I've used the Comp lifters quite a bit.
The thing about running a solid roller on the street is that you keep enough spring pressure to keep the valvetrain under control, and you keep the idle up a little so that the cam/lifters get
oil splash.