Fuel vapor return line req'd?

[timinator]

I recently installed a new fuel sending unit in my 69 Charger. I then found out the unit is for a 3/8 hose  and not a 5/16. The car was orginally a 383 car but now has a 440 so the original 5/16 line didn't fit on it. I installed a new 3/8 line which was used on the 440s. However, I now see it has a vapor return line on the sending unit which my car originally didn't have. Is this necessary to hook up or can I just block it off to prevent debris from entering the tank. I'm guessing the tank will vent thru the cap. My only concern is that the car will run OK. I don't see why not but thought I'd check to see if a vapor return line is necessary.  I also installed a high volume mechanical pump. 

[aifilaw]

Some caps for some years have vent holes intrinsic...I'm not sure if the '69 charger does, but I know the 72 does not.
I used my fuel return line as a vent line and just left it disconnected further up, you can do the same, but definitely run a hose off of it about 2-3 feet long so a random slosh of fuel won't exit and ignite, if its a side mount tank then of course don't let it act like a siphon, just use common sense.

I would assume the cap is not vent-able, so you will definitely need a vent, and running a short hose to somewhere pointless and leaving it open will do the trick

[Chryco Psycho]

the fuel pump will bypass without a return line so no you do not need a vapor return line

[deputycrawford]

     I went to NAPA and looked in the back of their catalog. I found a fuel filter with a 3/8 inlet an outlet with a 1/4 inch return line. I ran a return line to the tank. I fixed my vapor lock problem by doing this. I know you do not need the return line, but it can help. Just buy a 1/4 inch aluminum line roll from Summit and the said filter. I just choose to go the extra step and not have to worry. That's just my 

[jerry]

69  b-body cars 440-4bbl and 440 6-bbl cars came with 5/16 fuel lines and 1/4 vapor return lines. and do just as good a job as the 3/8 lines that everyone thinks they need.

[aifilaw]

unless you've upgraded it a bit, in which case the 3/8 is pretty much a pre-requisite due to fuel consumption.... the ballpark on that is around 500 hp though I believe

[firefighter3931]

the fuel pump will bypass without a return line so no you do not need a vapor return line

Cap off the return line on the sending unit and run it.....you'll be fine.



Ron