Valve adjustment result question

I adjusted the valves on my 48 Packard and found that 5 of the intakes had excessive clearance and most of the exhaust were okay. I made sure all were set correctly (engine running and hot). However, after finishing I was just doing a check of dwell, idle speed, etc and found my idle speed had dropped by about 40 rpms. I just checked it last week and it was exactly 500 and after adjusting the valves it dropped to 460. Is this normal if there was excessive clearance on intakes or is it just coincidence?

[Al Smeraldo]

A 40 rpm drop could be from differing atmospheric conditions on the days taken. If the valves are too tight you might have a drop in rpm. You would notice this in a rougher idle. Also you can hear this by listening for a popping noise at the carb (intake valve) or at the tailpipe (exhaust valve). Al