IDK what "batch" mine are but I bought a set of cnc Stealth heads in 2012. The only thing I did not like was the amount of work the pushrod holes needed to get enough clearance for the pushrods. I've been running them for over two years now and love them. The only upgrade I did to them was to discard the springs, retainers and locks they came with and install COMP parts. I had a good cylinder head shop check them over and mill them .050". The guy was very impressed with them especially considering the price.