My cousin who was a "stove bolt" savant would adjust the valves by making the engine idle down to about 450 rpm and adjust the valve while it was running. As some as the engine missed he would loosen the screw a bit then tighten the lock nut.
I had that same Weber setup on my 235. I ran it for a while and then went back to the stock Rochester. I got better gas mileage, but the engine suffered a very noticeable power loss. I found out later that the Weber is only a 200 CFM carb. I’m now going to put that Weber on a 216 since the stock carb is long gone. It will probably work better on a smaller motor. You have a nice looking car.
Just a comment from an old man who ran a garage for a living. Stove bolts inline sixes don't have to be noisy. The problem with the procedure you show is there is a drastic temperature change from the start to the finish. If your settings don't allow for it there will not be accurate. my procedure is getting the engine running and able to be loaded as in driving or cruising in a marine application. Shut it down and then check and set the number six-cylinder valves, they will be the hottest. Set the valve cover back on and wait till morning then measure the valve setting on number six cylinder. This is your cold engine setting. Use that to set the valve without temperature change for a more accurate setting. If you want it quit running reduce the settings about 1 or 2 thousandths. Tighter the settings the less wear takes place in the valve train and longer before needing adjustment. But hey I'm just a old, retired mechanic who worked on these for a living.
Unfortunately I’ve seen other mechanic damage valves that way. When you’re getting paid to adjust someone’s valves, doing them hot with the engine off, per by the book is a more accurate and safer when you’re working on cars that arnt yours
