My 347 pulls strong to 6500 with hydraulic rollers. Not sure what the springs are.
A 4.6 modular can turn 10,000 with hydraulic lifters. I know the overhead cam is apples to grapefruit, but there is a point to be made. To get to those rpms they use 0-5W
oil to keep the lifters from pumping up. My experiance, back when I was a puppy, with a 383 Mopar (with hemi valve springs) was that it would turn 7000+ with 10-40W, but with 50W the valves would float around 6700. My point is that springs and valve train weight are very important, but so is the
oil. I even suspect some of the very high
oil pressure that I read of the FE engines could also negatively impact hydraulic lifter.