Gas line vents??
 

So recently I made a few changes to the lt1 swap and now it's stalling each time I come to a stop. I added a new exhaust and changed some speedo calibration. It seems to run good untill it gets warm. Also, I was smelling gas for some reason so I started listening and heard a hissing. It was the gas tank, it had build up positive pressure. Not sure why but the lines, return and pressure lines both seemed warm. There is no positive pressure vent, so I'm getting a vented Cap to fix that problem. The hot fuel lines has me wondering though if that's normal. ???

Re: Gas line vents??
 

How hot and where on the lines? Could be many things, exhaust heat (depending on how your pipes are run), the pump could have been partially exposed and running a little hot, generally hot day...

Any of those seem plausible for your situation?