Stock fuel sending unit with return line?

[ddp]

I'm doing a TBI engine swap into my 71 C10 and will need to add a return line to the stock tank. I don't have access to any of my factory manuals right now, but I see that the LMC catalog lists a return line in addition to the fuel and EEC vapor lines. They also list about 4 different sending units, including different units for 72 auto and manual transmissions.

Right now I have the single fuel and EEC vapor lines with a single line sending unit. The vapor line attaches to the top passenger side corner of the tank. I'd rather not modify my original tank and sending unit and would like to find a two line sending unit for the stock tank. I've seen a picture of one in a C20 in a TBI conversion thread.

Does anyone know what specific year, model, and application came with a stock return line and two line sending unit.

Thanks.

[gonzo6869]

I just replaced my sending unit and tank about 3 weeks ago, the old one (don't know if was original) had two lines coming out of it as well as the ne one (Repo).

[chris91]

I have a question to add. I'm assuming the tank is in the cab, can you do a TBI conversion with the stock fuel tank?

[Bruce88]

I don’t know of a sending unit that has a return line for the in cab fuel tank or why there are more than one sending units are listed for the trucks. But if you have a EEC fuel tank and want to run a return line you might want to consider what’s shown below.

[stevencvn72]

'72 sender units had a 5/16th return line that'll work great with your TBI...and yes there's lots of folks here with TBI and TPI with factory "in cab" tanks.

Check out this thread. I posted it a while back when I was going through the same issue. Good luck
http://67-72chevytrucks.com/vboard/s...d.php?t=323887

[ddp]

Thanks for the replies. I am using the stock tank in the cab. Stevencvn72, your thread is where I saw the picture of the C20 with the two line sending unit. Have you gotten any further with your line replacement?

From what I've seen, a 72 with an auto trans used the 2 line unit and have found a good picture of one at:

http://www.carpartsdiscount.com/auto...html?3593=2633

According to the picture, the return line is a lot shorter than the pickup line and only extends a few inches into the tank. I'm wondering if you can hear the fuel splashing back into the tank if the level is below the bottom of the return. Or if the splashing somehow would cause a problem with the pickup.

[stevencvn72]

Since I'm running a TPI, I ended up pulling the stock return line in my new sender and soldering in a larger line. I didn't extend it much further than the stock one and haven't had any trouble nor does it sound like someone peeing in a stainless bucket. That probably depends on how loud your truck is. I usually don't let the truck go below a half tank since I don't have any baffles. I've had this set up for about 8 or 9 months now with no issues. My old sender was broken so I needed a new one anyways, but with your TBI, you should be good to go with the smaller return line.