I had a topic related to gas smell in this forum. The gas smell comes only when the truck is shut off and after about 5 minutes. Based on suggestion from experts here, I plugged the vent line and installed a vented cap - did not solve problem. Took it to a mechanic who thinks it is the carb and did some adjustment - did not solve the problem. The smell is strong inside the cab and in the engine bay. It is driving me nuts now.
I got about 25ft of steel lines and I want to go ahead and do a complete revamp of the fuel lines. I already have a new tank installed as the previous tank was shot. I am doubting the lines as they are pretty rusted.
My plan is to put new lines, and put a new pump. The old pump works, but pumps out about 8 - 10 psi. I do have a regulator installed now. If smell persist after the line and pump changes, I will tackle the carburetor. I just bought the darn thing about six - seven months back brand new.
Question - do I need to take the bed off to be able to plumb the lines? Or is it something I should leave to pros? I am good with the wrench and did most of the work in the truck myself.
Also, any advise on how to discover the gas smell will be greatly appreciated. I did read about some kind of tool that can detect origin of gas fumes. But I do not want to spend money if such a tool is just a gimmick.

1979 F100 302 engine. Carb: 600cfm Edelbrock with electric choke.

 

There is enough room in the frame rails to do it from under the truck. There is a rubber line that connects the tank to the frame mounted lines anyway. They should run on the inside of the framerail.