The other 359!! Love it!!

As Jerry said, it has to be a known value (and repeatable) the OP needs a reference to come into spec. , does a degree or 2 amount to much for a daily driver? No.. but OP has to have a foundation to build on. Having done headgaskets, means the rockers are probably all out of adjustment too! I think Techinspector and or RSpears had a link or writeup that was worthy of a How-To.. He needs to download it and follow the instructions.

And imho a Vacuum Gauge is also a requirement when checking / adjusting lifter / carb / timing. I don't make a move on my car without it, even mounted one in the dash permanent!