My understanding is the 440Source heads are "good enough" ootb but not "perfect". I will be taking mine in to my machinist to be checked over and will likely get a valve job; when I mentioned to him I was running those he said "I've seen them pick up 10-20 cfm just from a GOOD valve job."
I also try my best to buy stuff not made in China but I have to draw the line somewhere or I'll go crazy and broke. AT LEAST to me, 440 Source is an independent, American-owned-and-operated business that also tries their best to sell parts made in USA. The connecting rods, water pump, WP housing, head bolts, and a few other parts I got for my 440 build were all made in USA. Pretty sure the Hastings rings I got are also USA-made. Can't say for sure on the Icon pistons or MAHLE-Clevite bearings but I do what I can. I'm trying to buy as much stuff from 440Source as possible too as opposed to Summit etc. since they are a "small" business and also very close; buying parts from Nevada and being in Colorado, I typically receive them in 2-3 days. I personally think that is even more important; not supporting the huge corporations that outsource all their manufacturing to China without a second thought. Not saying Summit specifically does that but y'all know what I mean. Also if we support these smaller companies it will help them reach a point where they have the capital to invest in USA manufacturing. I think it's a safe bet 440Source would cast their heads in USA if they could afford it and still sell at the same price point.
OK I'm off my soap box now lmao