Help with 71 vent line, verse 72 and up.

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PhillH

PhillH

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MagnumMopar has really got me straightened out with the fuel connections to hook up my EFI system, I decided to go with hard lines from Classic Lines because they will bend me new supply and vent lines both in 3/8" instead of the 1/4" on the vent line, then Magnum's kit {which he actually took the time to draw up and plan for me, thanks Magnum} will connect it all. The thing is that Classic Lines only has plans for a 73 A-Body type RETURN line and I have a 71 VENT line, not the newer 73 RETURN system. Is the 71 four vent tank system and the newer return system they used in 72 and up the same bends even though they were for different puposes? I think they should have the same bends because the 108" wheelbase is unchanged.
 
There were "almost" changes every year from 70--74 in that vent system. Go to MyMopar, download the shop manuals, and look them up.

I would NOT use the 1/4" line for an EFI return. Rather, I'd buy TWO 5/16 or 3/8 feed lines and use one for suction, and one for return. You can buy senders with a return, or you can punch (not drill) the face of the tank and silver braze a fitting in there.

You MUST have a tank vent. you either need to leave the old one in place, or figure out something else. In my opinion, the way to do that is to duplicate the old 69 / earlier style vent, which was a tube teed into the top of the filler neck. That of course is in any service manual 69/ earlier.

One guy on here insisted on using a vented cap. in my opinion that is an invitation for fuel all over the side of your car.

"the main" differences in the evap stuff is that 70 (and 71?) had a separator can in the trunk, plumbed into the main tank, and to "up front." 72? 73? went to a modified fuel tank and had no external vapor can.

Here's the 69/ earlier vent system, and also "non CA" cars

242yckm.jpg


Below is a functional diagram of the 72 setup. The line from rear to front IS the vent

2r2q0ra.jpg
 
I do really appreciate all the info. But I was hoping somebody had an answer to my question. Probably not first hand knowledge because it is a sort of different different type situation, but I took a shot in the dark that maybe someone had already ran into this.
 
67Dart, I think your idea of buying two 3/8 feed lines is going to be my best solution with this.
 
I do as well. Regardless of changes in the vent bending, you can cut it or rebend if you need to "back there" to allow for your return mod
 
Yep, climbed under there and looked at what it'll take, looks like I should be able to bend it around slightly to get it right. Thanks.
 
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