i can idendify with vapor lock. alot of mopars have this malady in extreme heat. in the late 80s my 1968 imperial after 10 gals. of super in 90 degree heat, well, it started but when accelerating it just paused and wouldn't move. i pulled over and when trying to move again the carb blew back and the hood insulation caught fire, i ripped it out and that stuff is hard to put out! it was a sight seeing me with both feet stomping on it by the side of the road!