Poney up at least 6 figures for a 5 axis CNC and I'll see what I can do :P Right now, I'll drill some holes for you, reface your manifolds and make some simple bracketry :P
I've got a 6" cutter coming for oil squirter fitment to 5s blocks, however, I highly doubt the sucker is going to reach (well, it will, but only with a bit over 1/2" of cutter in the collet which I cant see working especially with such a long cutter, I might try my luck though, do the majority of the cutting vertically and just run a fine final cut over horizontally to ensure flatness, other option is a 3/4" 7" long cutter which will definitely work, but costs 4x the amount of the 1/2" x 6" long cutter.
Tooling currently shipping from the USA.