340 has a hard time starting when hot?
I had the same issue with my Duster. Like stated above the fuel boils. Even after my car sat for 1 hr it was hard starting and when it did start it was flooded with fuel. I would have to turn the pump off and on until it received fresh fuel. On my car I had to change the regulator to a return style and put it after the carb. Pictures below. The car did not do this with leaded race fuel. Only on pump gas going to shows. After I change it over it ran more consistent through temp changes. What I did is what you would do on a holley dual feed line with electric pump.
On a carter style this is what you want to do.
Most mopar V8's from mid 70's and up had a return on the filter for this reason. There was third nipple on the side that would flow back to the tank. The float in the carb will not function properly with hot fuel of today when the fuel is dead ended up against the needle and seat while hot. Adding a return eliminates this problem. They added the return to the filter and routed it back to the tank.
How to check if this is your problem is . After the car is hot and before you go to restart it. Take the fuel line off at the carb. Put a hose on it and run it into a container. Turn the car over until fresh cool fuel comes out. Put the line back on and it should start. I have done this 3 nipple filter on several cars that come here with this problem.
A cool can also works but then you need to carry Ice and use a shut off for the fuel before shutting the car down.
This new fuel is terrible in our carbureted cars. It is the float not working in the carb that causes this issue
I had the same issue with my Duster. Like stated above the fuel boils. Even after my car sat for 1 hr it was hard starting and when it did start it was flooded with fuel. I would have to turn the pump off and on until it received fresh fuel. On my car I had to change the regulator to a return style and put it after the carb. Pictures below. The car did not do this with leaded race fuel. Only on pump gas going to shows. After I change it over it ran more consistent through temp changes. What I did is what you would do on a holley dual feed line with electric pump.
On a carter style this is what you want to do.
Most mopar V8's from mid 70's and up had a return on the filter for this reason. There was third nipple on the side that would flow back to the tank. The float in the carb will not function properly with hot fuel of today when the fuel is dead ended up against the needle and seat while hot. Adding a return eliminates this problem. They added the return to the filter and routed it back to the tank.
How to check if this is your problem is . After the car is hot and before you go to restart it. Take the fuel line off at the carb. Put a hose on it and run it into a container. Turn the car over until fresh cool fuel comes out. Put the line back on and it should start. I have done this 3 nipple filter on several cars that come here with this problem.
A cool can also works but then you need to carry Ice and use a shut off for the fuel before shutting the car down.
This new fuel is terrible in our carbureted cars. It is the float not working in the carb that causes this issue