I've used 3 sets of EQs. The first set was great (bought bare and built up myself) the 2nd set was questionable the freshly built engine they went on drank oil, my son re rebuilt it at 6000 miles and turned it into a 408, and sent the EQs thru the machine shop with the rest of the engine) don't know if it's thirst for oil was in the heads or bottom end) the 3rs set was a complete disaster. (Engine didn't go 6 miles. Valves stuck and kissed pistons)
2nd 3rd set were bought complete "ready to bolt on out of the box" which they certainly weren't.
The first 2 sets came from Vegas, the 3rd set I picked up off the dock here in Chicago, got the last head off if 1 pallet, the 1st head off another pallet)
first set was bought in 2009, 3rd set late 2016, 2nd set bought somewhere in between.