Sheesh, I am really falling behind on posting. Well, I made some progress on the pushrod tubes. I made the tappet bushings according to plans a long time ago. But once I had all the parts & engine assembled to this point, I could see some major issues.
Number one, the pushrods enter the rocker boxes at different 3D angles. One angle component is related to how the rocker boxes sit on the head viewed from front relative to cylinder center line. The other angle component is because the intake & exhaust cam plates are fore & aft of each other, which is where the tappet/pushrod originate from. So intake & exhaust rocker box holes are different to each other. Something always seemed fishy with the plans in this regard. I could never make the parts fit in CAD, so so I drew it up from scratch. Things get more more interesting because the pushrod moves in a 3D motion. the bottom goes up & down an axis via the tappet, but the top moves in an arc via the rocker. So I found the min/max from cam throw & orientated the new hole center to the average point, then extruded a 3D hole into the rocker box plate. These aren't the actual drawings but hopefully show what I mean.