started getting a little depressed at the prospect of spending another bunch of cash on lash pads + aftermarket spring keepers, especially since i'm re-building another motor for this car...
took a moment to think about it and realized the one thing i hadn't measured was the cam... turns out it was the problem - it's a re-grind with higher lift and smaller base circle, and they dropped it into a stock cam setup. i measured every lobe and compared them to the cam in my original N47 head (the one that came with the car) and put all the data in a spreadsheet to figure out how they related to each other.
then, just for kicks, i pulled the cam, rockers and lash pads from the original head and put them in the new one and see how the geometry worked. i kept all the assemblies together (lash pad & rocker w/same cam lobe) and marked the rockers with sharpie to check the wipe patterns. the result: perfect! every rocker wipe pattern lined up exactly as it was on the original head, right in the middle, as set up by the factory in 1978.
so i went with it - cleaned everything up, slathered it in the "z paste" that came w/the re-surfaced rockers from delta cams and did a quick polish on the combustion chambers.
the N47 cam is internally oiled and the N42 is set up for a spray bar, and i didn't want to mess with doing both and wondering if i had enough oil pressure, so i decided to block off the spray bar outlets with some small aluminum plates and just rely on the internal oiling.
i'm hoping to get some time tomorrow afternoon to put humpty back together and see if it all works...
the measurements
Cam Measurement Comparison.pdf
spray bar block-off plates
chambers all cleaned up