just a thought on the nla 9 stand shafts.
Why couldn't we take the 5 stand/bolt shafts and carbide the 4 other bolt holes?
That is certainly doable!
What would be required to "retrofit" a nine stand shaft:
1) flip the new, currently available boat-style rocker shaft 180* so that the oil holes are on top of the shaft.
2) "notch" (identification witness Mark) the "top" of the shaft at each end just like the oem part. Or some other form of marking that would be shown in an accompanying instruction sheet. That is to show the correct assembly position when positioning on the head.
3) addition of n=4 additional holes for the rocker shaft/tower bolts. All rocker oiling ports are in correct position.
4) remove core plug from one end of the modified shaft and clean internally to remove grinding/drilling debris.
5) install replacement core plug.
6) treat with preservative film for corrosion inhibition.
I just did a "grind" spark test onna scrap shaft to check "hardness"...it is!
I've exhausted sourcing the bushings for the rebuild of the welded rockers themselves. Those two rocker assembly rebuilders were right...no parts available. That is a very thin steel shell bushing with the bronze friction surface with machined-in oil channels what do you think you could do for that refurbish but keep it cost effective?? The steel shell would also require a tig weld to retain.