I work on around 70-80 sets of heads a year or so, so I get to see alot of new/used stuff all time. Only broken LOCK I've seen in past few years was actually a brand new Comp611 11/32" with lash cap recess. It was on a new set of heads I had just assembled & was going to put on a motor I was building.... Well I needed to check something with checking springs after I had assembled the head, so I pulled pair of valves out of #1 cylinder to put the checking springs on & when I popped the locks out the one came out in 2 pieces... brand new lock busted just from being installed & having some load put against it. This was in a Comp 1731 tool steel 10 degree retainer. The grain structure of the metal looked horrible. Every once in a while you used to get a pack of locks that had a broken two piece unit in there.... Does'nt give alot of faith as to their metal quality.

I talked to one of my parts suppliers who is big into the valvetrain business about it & turned out he told me Comp had gone to a new offshore supplier for their 10* locks a few months prior to that set I had got. Needless to say that was last Comp lock I have used, I started getting them through a private source that has them made at Precision in NC, I buy in sets of 320 at a time & get real good pricing as well.

Hav'nt had any broken retainers in few years.... & the ones I have seen definitely were not setup right. Have seen maybe 5 or 6 broken springs here & there. Again usually operator error or some of that stuff was on sprintron Nascar heads that had 1000's of miles of spintron testing on them.