Running rich/stumbling after replacing spark plugs

KitCarlson said
Is the vacuum operated choke pull-off working? That should open the choke some once engine starts.

Also the #5 and #7 plug wires could have swapped positions. That will make it run on 6 cylinders, unburned fuel out exhaust.

I've made that mistake before, but that's not the case this time :)

Riff Raff said
How about the power valve? Any chance you had a backfire through the carb?

Now that would make a lot more sense, because yes, multiple times. When I first installed the new carburetor, it blew the vacuum advance line off and started chuffing through the carb. That was about 6 months before it started running rich and smoking though. Could that still be the culprit though?