I had one more thought, once an engine has had a cam lobe failure all of the metal from the lobe has rained down on crank and rods mixing with the oil turning into a laping fluid. You can't count on the filer catching it because it only filters about 10% of the oil. Internal engine wear is accelerated. When using a flat tappet cam you should run 15/40 oil all the time and use an additave such as GM's EOS for cam break in. The other grades of oil have had a lot of the zinc and phospherous removed due to emmissions requirements for newer cars. Sorry to be so long winded but this stuff is important to know for all old vehicle fans because the oils just don't have what it takes to protect our older engines.
