You said:
"I heat the eng up, adjust out all lash and then tighten 3/4 turn more."
Are you setting the engine to #1 TDC (Top Dead Center)and then to #6 TDC before you do any adjustment?
Also when adjusting to zero lash, loosen the adjuster and turn the adjuster to zero lash with your fingers, not a screwdriver. Then, using a screwdriver another 1/4 turn.
Sometimes weak lifters or lifters that have been "pumped out" will give a false reading of zero. When you turn the engine over without oil pressure the lifters loose oil.
Then, when you start the engine, after the adjustment, the valves are probably going to clatter because the lifters are not completely pumped up.
If you are sure that you have ADJUSTED THE VALVES CORRECTLY,
Run the engine, faster than idle, to build up the oil pressure and the lifters. The valves are going to be loud and noisey until the lifters are again fully "pumped up". You will find that after a few minutes or so, the valves will then start to quiet down.
My 235 has hydraulic lifters and if I turn my engine over by hand 2 or 3 times when I restart it the valves are noisey but then quiet down after the lifters are pumped up.
