408 hyd roller, too much spring pressure?

What is the preload set at? That cam is fairly aggressive and the spring pressures are quite a bit higher than stock (not crazy though IMO) but you shouldn’t have any problems with the stock roller lifter. You might have to experiment with different preload settings until they are happy.

Its set about one full turn from zero.
I have read that setting them just a bit from the bottom could be a way