The set of Stage V heads I had looked a lot like yours, the smallere exhaust ports, drill and machined for the future use of dual plugs and so on They where purchsed by the original owner to use on a seroius SS/AA car, he forgot to cll NHRA before buying them to see if they where on the approved replacemnt head list, they weren't So my customer bought them at a good price and we used them on his blown street Hemi project Stage V is really hard to get contact with, there way to busy, I guess, to take care of new business