Yeah that's crossed my mind but I'm trying to ignore it Rebuild 2014 probably over 50,000 since then. We drive it a lot, did Route 66 a couple of years ago.
Why I asked was that carbon buildup on the valves / seats can cause it to not let them fully seat. And with trying all the other things, tuning, timing and such. Get some fuel system cleaner and run a bottle.
I was doing a leak down on a “timed out” race motor a few weeks, and the valves were not fully seating due to the carbon buildup on the seats / valves.
With the amount of miles you have since the last rebuild, and the amount of shitty modern gas that was burned to get that many miles, it makes since.
