A noisy lifter is a disaster waiting to happen. It's like repeatedly smacking the top of the valve stem with a hammer. You'll experience mushrooming of the top of the valve stem, and increased wear at the tip of the rocker arm.
A camshaft lobe has a short area of slow lift called an "acceleration ramp" which allows the clearance between the lifter, pushrod, rocker arm, and valve stem to be taken up gradually before the quick lift of the valve begins. It just happens that the height of the acceleration ramp is equal to the clearance the manufacturer specifies. If any clearance is added to the factory spec, the speed of movement is increased after the ramp height is taken up, resulting in hammering of the parts instead of a smooth valve lift.
Make 'em noisy if you want, but if you do, you're destroying the valve train. Better use the right hot adjustment specifications!
A running adjustment is a total waste of time. The 261 is supposed to have a mechanical lifter cam, and the idea that adjusting the noise away is a proper adjustment procedure is an incorrect assumption where hydraulic lifters are concerned. Stop each cylinder on TDC compression by using the companion cylinder adjustment method AFTER running the engine at least 30 minutes to get it up to normal operating temperature and use a feeler gauge to get an exact clearance on every valve. If it's noisy after that, install a new cam and lifters.
Jerry
