Thought I had a vapor lock on a 100 degree day when the 40 started to die (50 block, bored to 3 and 3/8), dual 9 super 7s on a eddie meyer high rise. Pulled over and found gas gushing out of the back side of the rear carb. Pulled the carb off and blew out the inlet to the float and re-installed. Still leaked out of the back side of the carb. Installed the replacement from Speedway and have had no problems this week. Also haven't had any problems with the front carb. Forgot to mention earlier I am running an electric fuel pump through the stock pump at 2 psi.