Engine tech has parts manufactured elsewhere and they put their brand name on it. Many of them are likely the same parts as those with other company's names on the box.
I used their kit when I rebuilt my 225. My impression is they pretty much use name brand parts that they gather up and package into a kit. My machinist who has been doing this since 1962 said the parts were good. In the case of my /6 it included Silv-o-lite pistons, Hastings rings, King bearings and no-name gaskets. I suspect they were McCord but not sure.
Just used some of their stuff in a chevy. Of the same opinion it's just re-boxed stuff. Not complete yet, but the gaskets seem of decent quality. Headgaskets appear similar to Victor gaskets I have used in the past. Graphite coated. Never used McCord so can't say for certain either. Got the ET stuff through Rock auto.