69 vs. 70-72 fuel tanks

[MikeB]

I'd like to replace the 54 year-old fuel tank in my 69 C10. But I want to use a tank with EEC to get rid of the gasoline smell in my garage.

Vendor pictures show the 70-72 tanks as having a tube close to the filler neck, but the the sending unit also has a tube next to the fuel line tube. Where are these connected to? Does one go a charcoal canister, and the other to a mechanical fuel pump with a return port?

And did the factory run rubber lines all the way to the engine compartment?

Oh, and will a 70-72 tank bolt in exactly like my 69 tank?

Thanks.

[jnewt]

This thread has the info you require. http://67-72chevytrucks.com/vboard/s...d.php?t=845195

[jnewt]

Originally Posted by MikeB

Vendor pictures show the 70-72 tanks as having a tube close to the filler neck, but the the sending unit also has a tube next to the fuel line tube. Where are these connected to? Does one go a charcoal canister, and the other to a mechanical fuel pump with a return port?

And did the factory run rubber lines all the way to the engine compartment?

Oh, and will a 70-72 tank bolt in exactly like my 69 tank?

Thanks.

The second line on the sending units shown in pics is the return line. From what ive gathered, the return line was introduced in 72 on automatic trucks to help with vapor lock. Manual transmission 72s and previous C10s had the senders with supply lines only. Also note that 72s use the larger 3/8 fuel lines. Keep that in mind, depending on what engine your going with. You may want to use a 72 sender and lines (dont forget the pump to carb hardline, its 3/8 also). If your bot going to run a return line, you can use a sender for a 72 manual transmission truck. That will give you the 3/8 supply line and no return. Note: my truck was originally a 72 manual which has been converted to an auto. I dont run a return and have never had an issue with vapor lock.

No, rubber lines only connect the hard lines.

Yep, the new style tank would bolt in but you would also need all the EEC lines. Both in cab and along the frame to the engine compartment. I used a Spectra brand tank from Rock Auto. Bolted right in and only need a very slight tweek/adjustment to the filler neck to center it in the body. Very easy to do using a large pipe or floor jack handle.

Tank
https://www.rockauto.com/en/moreinfo...pt=6268&jsn=11

Sender 32-4024 (72 manual)
https://www.lmctruck.com/1967-72-che...and-components

[MikeB]

My truck sender tube is 3/8" so I should be OK there, unless there's something different between mine and 70-72. The rest of the fuel line is 5/16" because the truck's original engine was a 307. I've never had a fuel starvation problem that I know of, but have been meaning to convert to 100% 3/8" line.

I don't plan to run a return line, so should be OK there.

Looks like my major task will be running the EEC line. But I don't understand this pipe and hose routing (from the other thread) at all. No charcoal filter? Bizarre.



Maybe I'll just forget about it. I read an article awhile back about how the gas smell in the garage may be fuel evaporating from the carb, and a way to cure the problem. Makes sense because I mainly notice the smell after a drive. Have to see if I can find the article.

[jnewt]

Ya those EEC lines inside the cab just make a loop up inside the passenger side of the cab (guessing to prevent fuel from entering them). That line then runs through the floor of the cab along with the fuel supply line from the sender. The lines parallel each other along the frame to just past/forward of the fuel pump. Rubber line then hooks the hard EEC line to the evap canister which is mounted kinda below/between the battery and fender

[MikeB]

Originally Posted by jnewt

Ya those EEC lines inside the cab just make a loop up inside the passenger side of the cab (guessing to prevent fuel from entering them). That line then runs through the floor of the cab along with the fuel supply line from the sender.

Thanks, man. Makes sense now.

[Steeveedee]

Might be a lot less work to install an exhaust fan in the garage and put it on a timer. Adjust the timer to turn off when the stink is gone.

[jnewt]

Originally Posted by Steeveedee

Might be a lot less work to install an exhaust fan in the garage and put it on a timer. Adjust the timer to turn off when the stink is gone.

true true.

Even after acquiring and running all the lines, you will still need to acquire then rebuild a EEC canister. Which is a whole task itself. The canisters are sealed and not meant to be rebuilt.

[MikeB]

Originally Posted by jnewt

Even after acquiring and running all the lines, you will still need to acquire then rebuild a EEC canister. Which is a whole task itself. The canisters are sealed and not meant to be rebuilt.

I replaced a 250-six with a 350 in an 82 C10 several years ago. I left the OE tank vent line connected to the vapor canister, but didn't have EGR or the proper devices or carb to connect all the canister's ports. Drove that thing for another five years and never once smelled gas. Apparently the filter (filters?) were still working and vented the filtered air to atmosphere through a vent cap.

I think I can still buy a new one, but I'd need to find a place to mount it and make a bracket.

Not too complex.