I think Tom cuts down a 1.94" valve to get that size. The PES plates are still available, a set is currently on ebay as a matter of fact. From what I have seen posted and mentioned by others, they seem to require more patience and work to install them. I personally can't confirm or deny any info regarding performance #'s between the standard lumps vs. the PES. I think Tom as well has used both styles before and could expand on this from his experiences.
