The Siamese branch in the older head is very much “T” shaped and quite different from the “V” in the later head and the builders helping me didn’t think a lump would provide any benefit there and that altering the short side turn radius to resemble that which is on the lumps would be best. They did however suggest a “turtle” on the back wall might be something the flow bench will like. On Saturday I plowed in from the top of a head and milled a NPTF dryseal pipe thread and would give it about a 70% chance of sealing as is. Drilling the holes and then a bit of brazing on the inside lip of the hole to increase the thread surface a few turns before milling should put that at 100% so a Rajo type conversion looks pretty easily doable.
