I get tremendous Vapor Lock problems when driving slow like in cruising or heavy traffic on warm days (not hot just warm) when it is above 75 degrees F.

My car has a 396 with a Holley 750 DP, headers. It creates a lot of heat. If I remove the aircleaner (3 inch open GM type) the problem is less severe.

I think that the aircleaner creates a pocket of hot air around the carb and there fore creates vapor lock.

So my idea is to put on a return line, since it is a Z/28 it doesn't have that from the beginning, to solve the vapor lock troubles.

My question is where from should the return line go, I have seen pumps that have return lines and I have seen fuel line blocks that have it. I figure the closer to the carb the better.

I would be glad for some feedback.


Thanks


Jan

Some Pontiac GTO's, 68-72 I know, had fuel filters with a return line, 1/4 inch line was used.

I imagine one could use this as a source of return line, say to the supply line at the tank, by Teeing into the line. Ideally, one would want to return the fuel to inside the tank, but, this would require removing the tank sending unit and having it reworked to support a return nipple.

You might check your supply line to make sure there is not a vacuum leak, e.g., pinhole allowing air to enter before the mech pump.

An old shadetree fix was wrap the fuel line with alum foil, Reynolds Wrap, and attach wooden clothespins to the line about every three inches. This set-up would dissipate heat very well.

there are some high temp fuel line hose covers in jegs and summit. slide them over the fuel hose and it should help, and it doesn't look too bad either. also, i haven't tried one but they make a heat sheild that bolts under your carb (aluminum plate) that helps disapate heat. maybe someone here has used one before and could comment on it.i bought some aluminum fuel line when i installed the tpi init on my camaro. i used the original line for the return and the larger aluminum line for the fuel line. wasn't very hard and the aluminum tubing was pretty cheap. just be sure you run it next to the factory fuel line and i put the plastic wire wrap stuff over it to protect it. and don't for get to run it away from the hot exhaust pipes.