The vent line for a 71 ECS and the vent line for a 73-74 are both 2 peice lines. Both vent lines stop at hte lower frame rail and then a 2nd line goes from there up to the engine. The 71 2nd line ends right near the rear of the passenger valve cover, then a short hose goes from it to the breather.
Here's my 71, see the capped off line by the blower motor? it connects to the breather and is the vent to my gas tank, higher up than the gas tank.
The later 73-74 vent lines comes up by the engine in front of the passenger valve cover. I can't remember how it get's to the charcol canister from there. I'm going to connect mine to the breather, just haven't done it yet.
If I was to do it again on my next 74 that I'm working on, I'm going to use a 73-74 vent line in the rear and the earlier 2nd vent line in front so it comes up like my 71 car does. Either way it right and up above the gas tank and close enough to connect to the engine crankcase. It don't have to connect through the breather either.
Dang is it me or is Photobucket slow!!! I can't get to my pictures very quickly.
Here's my motor today, You can see the upcapped vent line sticking up behind the heater hose in front of the valve cover.
I have been looking for 2 or 3 nipple breather which I think I have somewhere, just haven't looked real hard yet. I'm not paying big bucks for one from a swap meet or something. I may drill and tap a 1/8" pipe thread in my stock breather and add a 1/4" barbed nipple to connect my vent line if I don't find one.
For now I have just left it open even though some dirt could get in there. Yea I know a 1/4 fuel filter stuck over it may be enough venting capacity. I'm not taking any chances, I want it wide open until I get it connected to the breather.
I have driven this car a lot since I put these lines in and it works great with a stock mechanical fuel pump.
The metal fuel filter that I added was/is a experiment/tempory because it is in addition to the factory filter in the hemi VS bolted to the fuel pump. I'm gonna take it out and go back to a straight line like I ran for over 10 years. It(the second metal filter) didn't give me any trouble even when it got really hot idling in Heath traffic for up to a hour at a time.
I wanted it in there after replacing everything just for a while to protect my perfect running carb. I don't like there because it'll absorb heat where it's at.
Hope all this helps you or someone.
My hemi vapor separator is painted silver, tank tone and has a .057" nitrous jet stuck in the end because the VS had a .042" hole, too big!
I slipped about 18-24" of spark plug wire heat shield over the suction and return line up by the engine before I bolted it to the frame rail to protect it from header heat. That's the red stuff down there.
Thats what I've done too. As long as the tank remains vented (either by a different line or the fuel cap) you're fine
If you use one nipple to vent it then it's not vented in every possible way you can park your car. There's only one way to properly vent a stock challenger gas tank.
Amazing how boats even run then with all that water.