Yo guys. When i drive my dart aggressively, the slant 6 rumbles for a few seconds after i shut it off. A few guys told me to put in a few tanks of super, and that helped a little bit but not completly....should I rebuild the carb?

 

When you say "rumble", I assume that you mean that the engine runs after you shut it off. I will base my reply on that assumption. The term given for this is "dieseling" because the engine shortly runs due to hot spots in the heads instead of a spark from the plugs. This can be because of a couple of things. A) Check your idle speed. Too hight and the inertia in the crank and flywheel will keep cranking the engine. Too low of an idle speed and too lean of a gas mixture will result in a high enough temperature in the heads to fire any mixture of gas. Set your idle mixture screws if this is your problem. B) Check your timing. This goes hand-in-hand with carburator adjustmants. Also keep using the best gas you can get. I hope this was of any value to you and good luck. This problem is not bad but it sure can be annoying!

 

Sounds like "dieseling". If fresh gas and timing does not cure it, it could be hot spots from carbon buildup in the cumbustion chambers or on piston domes. They can work like the glow plugs in those flying model plane engines. If it really runs on and on, try shutting the engine off while it is still in gear.

 

My duster did that too.
Needed carb adjustment and timing that was all for me.