A lot of stuff is made in china and checked/finished here.
scat anin't crap
I have chinese roller rockers that I've run with success for a long time now, they were chinese and cost little.
With the exception of a few new products and certain parts that are used beyond their intended purpose [proform]... the china stuff ain't 'all' bad. We've given them the metallurgy and they've had it for a while now.
So many of these made in the usa parts have started out in china only to be machined here [if you are lucky].
you're an engineer...right?
I really think you got in over your head, didn't know how handle the speed bumps, didn't know more than the machinist and threw in the towel.
Guys that wanna learn the truth wait and work it out and only last resort post and ask if anyone else has a clue, they are determined.
There are people who are hands on in every aspect and then there those who 'seem' to understand or think they do...but in the end always end up throwing money at it, never really figuring it out and leaning from it.
And springs are unique to the cam profile...don't expect ootb springs to work on a whatever cam you have...and tech lines and there operators are useless btw
this where knowledge/Experience comes in.
Like if your large body rocker hit retainers n such, what does that tell you? it tells me to run a smaller diameter spring, maybe a beehive, not junk the rockers.
But hey...if someone was to look more into what is required to run a certain combo of parts...which sometimes means buying and returning a few items, then eveything would work out.
My point is...save your slighted comments about stealth heads until you really know what went wrong and if it was the part or the user that installed the part.