Chevy 350 Lifter tap - valve clatter
OK, now I'm frustrated - I have a Chevy 350 in my 76 CJ 7 - for a few years I've noticed (can't ignore) a loud on and off valve clatter / lifter tap when my engine heats up. After adjusting the valves to no avail, I noticed that several (2-3 per side) push rods did not have oil coming up through them. I pulled these and cleaned the crud out, and then I decided to tear appart the top end and pull and clean the lifters / and do a kerosene engine flush. After very thoroughly flushing and cleaning the engine, tearing down the lifters, soaking them in oil & tranny fluid, then pumping them back up, I reinstalled it all by the book.
When I got it up and running I set timing and adjusted the valves - hoping the additional clatter I was now hearing would go away, but it's actually gotten worse and steady!!! I have consistent loud tapping from both sides of the engine at cool temperatures. I am still getting very very little oil out of several pushrod holes on each side. My oil pressure is very good, and a vacuum test shows no issues with the valves. I wonder if I should replace the lifters now, or should I try to pump them up again?
I've only run the engine a total of 2 hours since reassembly. If there is a way to pump up lifters while in the engine, can I do this without the agony of pulling intake apart again??? Any other possible reason for no oil coming up pushrods???