10W40 too light?

So you have a fast rate of lift cam and honest to goodness anti pump up lifters and you are wondering why your engine is noisy. If they are real anti pump up lifters, then you must surely have adjustable rockers like they absolutely REQUIRE. The correct adjustment for them is between .002" preload and .002" lash, like a solid cam. I prefer running them loose at .002" lash. Put those fast ramps together with anti pump lifters and that engine will make noise regardless of oil.

If you wanted a granny quiet engine, you should have built it stock.