How can you tell if EQ Heads are from New Zealand Foundry

Ive had 3 sets (well I have had 2 and talked my son into the 3rd) My 1st set back in about 09-10-ish was GREAT. I bought that set bare and filled them with the best parts from 3 sets of original cracked Mopar heads. set #2 went on my son's Ramcharger, after 6k miles that thing ended up an oil eater, so he took it apart again and made it into a 408. this set was "fully assembled, (supposedly) ready to run". both of these were LA intake pattern. as a switch to the 408 he sent these heads into the machine shop before his bottom end parts and said that the machine shop found "issues" with them.
Set #3 I bought for my Durango to replace a cracked set of OE, again supposedly "ready to run out of the box" and teh only set I bought of the 3 sets with the Magnum intake pattern. This set DEFINITELY had problems, contributed to coating me a complete fresh rebuilt bottom end. Valve clearance was too tight, exh valve on #4 stuck and got kissed and bent by a piston. Machine shop said that he has had heads that sat outside for 30 years on teh ground that came apart easier. He had to pound out most of the intakes because they were so tight.... and had a set that he ordered for a customer that ate themselves because they were so tight on guide clearance. while on dyno breaking in a cam.
Mine ran ~2-2/2-3 hours max, including a 6 mile maiden voyage from which I had to be towed home.... I was beyond PISSED at EQ. That set of heads was bought around Oct-Nov 2016. I picked them up "will call" at EQ's Chicago location, came home took them out of the box and bolted them on. I had gotten the last head from one pallet and the 1st from another. GOOD RIDDANCE EQ