Most all summit brand parts are USA made or assembled here due to Tariffs. Even the timing chains which are good . Forgings are from China for most all crank suppliers .
The machine work is done in the USA. So quality is only determined by the machinist on that job/crank. Seen good and bad from all suppliers. Some really bad expensive cranks and some really good cheap cranks. Machine work and heat treat determines the quality. Some of these suppliers have Real idiots doing the work.
I ran into the same issues with interior pieces from reputable suppliers. Try to by from a 3rd party that will have your back on quality issues. Big companies could care less about the one time buyers. That is why not to buy direct if your not a frequent buyer for a business.
One thing I can tell you all is "Dantes parts" always stood behind what he sold for restoration parts. I like buying from a 3rd party like him.
"Summit Racing" is great. Like "Dantes" they will take defective parts back without question so we use them a lot. Also "Engine Tech"