I said to you when we was doing your car what someone has before on here, maybe on that Pushrod thread, that the more lift you have, the closer the pushrods get to the head, and yours are close, hitting slightly going by the slight witness marks.
The fact they're close but NOT touching normally when turning the engine by hand, but clearly have, suggests, as Clarkey mentions, that they flex under load, which is when they hit.
Also, you've got bigger valves, so more surface area for the cylinder pressure to be pushing against, making it harder for the pushrods to open them under full boost, meaning more likely to bend the cunts now, than with your old head with stock size valves, when there was never an issue.
More power and boost is more cylinder pressure too, again making it harder to open, again giving your pushrods a harder time than it used to be at 23psi.
IMO it's not valve springs as the root cause, and even IF it was you'd be taking the head off to sort that, and then you'd be far far better off just enlarging the pushrod holes and fitting them Isky rods, rather than fitting weaker springs.
Weaker springs is like putting a plaster over something rather than actually fixing it in my eyes.
Considering how mild the witness marks are, that in itself isn't the issue, but the fact some seemed slightly bent at the bottom 'may' be, but even that I'm not convinced as we checked the valve clearances prior to that and they were a little tight if anything, not loose how a bent pushrod would do.
It's about look at this logically rather than changing bits willy nilly.
The only part not checked, and a part well known on engines for being noisy, is the lifters/followers. But on 5s I've no knowledge of them.
First up, have a look at the pushrods again before making more decisions.
