O.K. I spoke with Ken at 440 Source. He said that the early batch of heads had issues but the new ones don't. The new retainers and the locks are the same as the ones used on eddy's. Also the chambers have been reduced to 80 cc's to eliminate the head gasket issue. Thanks for all the input.

i have a set of them on my 512, we put comp locks on for good measure, mine were a very early set, no problems.

Mine are a first batch set, I installed the updated retainers/locks and bolted them on. I'll be pulling apart my motor again this spring so I'll be able to see how they've held up so far.

I have a set from the first batch on my car. Changed to Comp retainers and locks, and touched up the valve job. No problems and I like the stock look.

I knew the parts issues had been taken care of. The assembly/machining issues still exist. One poster said "[his] guy is picky". The picky ones are simply making sure it's done right. Production line machining and assembly simply gets you production line quality. You will get more life and more power from having the parts checked and the few issues fixed straight away. And isnt that why you're buying new heads?