Runs lean. No matter what you do. But I found it

[Bobby Sixkiller]

Long story short. I’ve been fighting a lean condition on my challenger. For a long time. Pulled intake. Re sealed. Change carb. Re jet carb. Rich it way up on the jets. Swapped fuel pump twice. And the pushrod. Finally I replaced the intake. Carb. Fuel pump all together. Fixed. Runs like never before. After all is done and I’m happy with it. I’m picking up my mess. This is what I seen. No dam plug learn something new every day

 

[493 Mike]

Did you have a block off plate on the EGR valve port on the manifold?
Mike

 

[Bobby Sixkiller]

I had an egr valve on it first. Then put a plate on it. But it had to be pulling exhaust all the time. I’ve just never seen one of those pulled out. Never taken one out. See no reason to ever take it out. The small one on the other side is gone too. Previous owners had to remove them. And I overlooked it before.

 

[PurpleBeeper]

wow....

 

[Bobby Sixkiller]

Not sure how I overlooked that but if anyone has trouble getting a carb dialed in check the plug. I’ve never even thought about taking one of those people lugs out. But someone must have

 

[RJRENTON]

Long story short. I’ve been fighting a lean condition on my challenger. For a long time. Pulled intake. Re sealed. Change carb. Re jet carb. Rich it way up on the jets. Swapped fuel pump twice. And the pushrod. Finally I replaced the intake. Carb. Fuel pump all together. Fixed. Runs like never before. After all is done and I’m happy with it. I’m picking up my mess. This is what I seen. No dam plug learn something new every day View attachment 1281251

IMO....The first generation 340 using the Carter Thermoquad (1972 ?) Carb, used fixed, removable orifices under the carb directly into the exhaust crossover passage. This supplied a FIXED volume of EGR all the time, there was no external EGR valve. The EGR valve came later. The FIXED EGR orifices caused fuel percolation, hot starting issues, PP fuel milage and generally terrible performance. The quick fix was to remove thd fixed ofifices, braze the ofifices closed, reinstall, and go down the road without issues. One of Chrysler's bad ideas. Just talking out loud.....
BOB RENTON

 

[1967coronet]

Long story short. I’ve been fighting a lean condition on my challenger. For a long time. Pulled intake. Re sealed. Change carb. Re jet carb. Rich it way up on the jets. Swapped fuel pump twice. And the pushrod. Finally I replaced the intake. Carb. Fuel pump all together. Fixed. Runs like never before. After all is done and I’m happy with it. I’m picking up my mess. This is what I seen. No dam plug learn something new every day View attachment 1281251

Good catch !