good job, sounds like it was off a full tooth, glad you have it fixed

If this problem just started, my guess is your dist gear and or cam gear is bad. Timing doesn't just change that much by itself.

Its that or someone installed the plug wires one cylinder off on the dist cap.

Who was the guy that suggested timing being the issue, and was told that's probably not it?
Oh yea me...... Glad you got it fixed.

Are you sure when you changed the carb out that you someway somehow turn the distributor accidentally without knowing it. I believe your first problem you reported was the motor would not stay running under 1000 rpms ONCE WARMED UP but the engines ran strong POST # 1 ? correct ? Keep in mind, he put a brand new carb on as well.

Couple things here, the engine after new carb would not start and then you find out distributor was 1.5 inch out ? If the distrib was that far out with your old carb the engine most likely wouldn't start or if it did start most likely would be back firing plus poor throttling thru out the rpm range.

The carb was changed to brand new, IMO was one of the problems to begin with, not saying the only problem but really think it helped clearing up your poor idling quality. Also sounds like he is running on the water hose no load so water testing might be a little different of engine running quality (loaded).