Fuel line routing

by Silentknight85 Sun Apr 17, 2016 3:16 pm

Hey guys. When I got my car back from the toolbag that was supposed to do the body work (but failed), I ended up with no fuel lines. I bought some stainless steel fuel lines, but I do not know how and where they run. Honestly, I don't even know which end of the lines are towards the engine and which ends are towards the tank. Does anyone have a routing diagram, per chance? Or some other information that may point me in the right direction? I've searched all the usual resources and throughout all of my service manuals and I'm coming up blank. Thanks!

by Hawk03 Sun Apr 17, 2016 5:58 pm

Here is my routing on the right side. The brake and fuel vapor lines are running on the left side of the frame. You can see the end of it in through the front cross member.

Fuel line routing 20130715

by Joe73 Sun Apr 17, 2016 5:59 pm

Take a look at my build thread. It has frame pics with all the new lines installed. The front of the fuel line goes through a hole in the engine crossmember. A rubber hose goes on the end of the tubing and to the fuel pump. Any questions just fire away.

https://www.g3gm.com/t8584-1973-chevelle-ss-350-4spd-build

by Silentknight85 Sun Apr 17, 2016 6:27 pm

Thank you guys! Both of those are very helpful. I must be missing something on my build, though. I did buy the fuel line and the vapor line. I originally thought the vapor line was a fuel return line, but I now know that is inaccurate. I do not have a vapor canister (didn't come with the car, but it's not needed if the gas tank is vented, right?) Isn't there supposed to be a return line, as well? Sorry for the lack of knowledge in this area, but again, I have no original lines or parts to go by. Thanks again!

by Joe73 Sun Apr 17, 2016 6:42 pm

No return line. Yes, as long as the gas tank is vented, you can skip the vapor line.

by jerry46765 Mon Apr 18, 2016 11:23 am

It depends on the year of vehicle and how your car was optioned. I have a '74 Big Block Chevelle that has a 3 port fuel pump (inlet, outlet, and return). The factory supply and return lines run on passenger side frame. The fuel tank vent runs up driver's side frame to canister in front of LF wheel but your '73 didn't have a canister unless it's a CA car. Thanks -

by Joe73 Mon Apr 18, 2016 11:52 am

My 73 has a canister and it's built in Baltimore. But no return on mine.

by thatfnthing Mon Apr 18, 2016 1:16 pm

Ditto on canister, built in Oshawa.

by 73ss Mon Apr 18, 2016 1:52 pm

I'm fairly sure that the 4 barrel cars got the return line. My 73 was a 2 barrel & only had the single feed line. Some years ago I had the sending unit rebuilt and they added a return port. I ran a return line and it made a huge improvement with hot starts and vapor lock. I switched to a stock return type pump as well. Ditto on canister & Oshawa build here.

Joe was your 73 a 2 barrel car?

by clanceman427 Mon Apr 18, 2016 2:54 pm

No, My 73 350 4v did not come with a fuel return line on the passenger side. only the supply line on the passenger side, and the vapor line on the drivers side. it did come with the cannister and it was Oshawa built. didn't all 73's come with the cannister/vapor line as part of the country-wide emmissions standards?

by jerry46765 Mon Apr 18, 2016 3:15 pm

Big Blocks got the return lines. Small blocks did not.

Not sure what build plant location has to do with canister? The origin or location of purchase was what I was thinking, as in CA emissions listed a canister and air pump.

I bought a California origin '73 Monte Carlo and thought the canister was part of CA emissions. But looking at the build sheet, it isn't called out. Neither is the air pump? Maybe it was standard equipment by '73?

Anyway, big block return, small block no return.

Thanks -

by Joe73 Mon Apr 18, 2016 4:07 pm

Yes, mine is a factory 350 , 4bbl. Just the feed on the pass side and vapor on the drivers. No return. It also have the a.I.r. pump.

by thatfnthing Mon Apr 18, 2016 4:08 pm

jerry46765 wrote:Not sure what build plant location has to do with canister? The origin or location of purchase was what I was thinking, as in CA emissions listed a canister and air pump.

I think the point was that all 73 cars had the canister nation-wide regardless of where the car was built or shipped to. Mine had the air pump also.

by 73ss Mon Apr 18, 2016 8:33 pm

jerry46765 wrote:Big Blocks got the return lines. Small blocks did not.

Anyway, big block return, small block no return.

Thanks -

Did not know that. That would explain why when I swapped in the big block it had alot of vapor lock, hard start when hot issues. I had a big holley mechanical pump and the fancy AN type lines. Nothing but a vapor locking PIA. I ran the return line, installed a stock for 73 pump and a stock pump to carb line. Never had a hiccup since, Once in a while but it's 90 or above outside. Goes to show the factory knew what they were doing. Also I got the motor from a 73 caprice, it had the smog pump, I still have the pump & exhaust manifolds with the smog tubes stashed away.

by ant7377 Mon Apr 18, 2016 9:04 pm

My 73 has or hopefully HAD a little vapor lock issue with the heat cross over under the carb getting the carb too hot and stinking up the garage too. Its sll stock 454 with smog pump and all return lines. I judt blocked off the heat crossover. Left a small hole in the rigjt side one to keep the choke working

by Silentknight85 Sat May 07, 2016 6:11 pm

Thanks to everyone who contributed information. I FINALLY got the lines installed today. I must say that I did not know the pre-bent stainless steel lines would be so far from just being able to install. They do not make it easy. I had to change the bends in every line to get them installed. But without you all, I'd still be guessing which end is front vs rear. So, thanks again!

by sportster_restorer Sun May 22, 2016 9:38 am

[quote="jerry46765"]Big Blocks got the return lines. Small blocks did not.

1974 Laguna, was originally a 400 SBC with 4 bbl carb (now it has 350 due to the 400 going south somewhere in redwood country, so I discovered). California car sold originally in Reseda, CA. It has 3 lines on the fuel pump; inlet, outlet, and return. I think all the 4 bbl carbs had it, not just 454s.

by Joe73 Sun May 22, 2016 10:02 am

My car is factory 4 bbl small block and does not have the return line.

by Silentknight85 Thu Jun 02, 2016 9:47 am

I'm able to buy a vapor canister from opgi, but not a mounting bracket. I currently have neither. Since I cannot find a mounting bracket (I've checked all the usual websites and ebay), I think I'm going to go without a vapor canister. That being said, I need to vent the gas tank. Is a vented gas tank cap appropriate for this? Is there another way that the gas tank should be vented?

by Hs1973 Thu Jun 02, 2016 12:13 pm

I just put the fuel tank vent hose along side the fuelline and left it open inside the side of the frame just in front of the rear wheel. It has worked fine no problems what so ever. But remember to put a fuelfilter on the end of it so the Vabors can exit but debris cant enter and make it to the tank.

I have had a lot of 73s and all have had the airpump and canister, all had return Lines, exept one that was a 2 barrel it had not. This was here in Europe. And since we dident have a law forbidding removel, the pump and tubes where disgarded and the holes blocked off in the manifolds.

by Mcarlo77 Thu Jun 02, 2016 4:49 pm

Silentknight85 wrote:I'm able to buy a vapor canister from opgi, but not a mounting bracket. I currently have neither. Since I cannot find a mounting bracket (I've checked all the usual websites and ebay), I think I'm going to go without a vapor canister. That being said, I need to vent the gas tank. Is a vented gas tank cap appropriate for this? Is there another way that the gas tank should be vented?

I'm running out to the yards this weekend. Want me to look for a canister and bracket?

by Silentknight85 Thu Jun 02, 2016 5:22 pm

Mcarlo77 wrote:I'm running out to the yards this weekend. Want me to look for a canister and bracket?

I would greatly appreciate that. Thanks for the offer! I am unaware of any yards around me that have anything else than modern vehicles, so I'm not able to scavenge efficiently

by Silentknight85 Mon Jun 06, 2016 9:55 am

Inlinetube.com and classictube.com both have the fuel return lines for the 73-77 chevelles. I don't care for Inlinetube's ordering system (total amount charged is emailed after the purchase is processed). I was able to find the classictube line on Summit, but Summit states that it's for a Monte Carlo only (classictube says it will work with the Chevelle). I know the MC is closely related and is also an A-body, but now I'm concerned that they're might be differences. Does anyone know if an MC fuel return line is the same as a Chevelle's? Thanks.

by thatfnthing Mon Jun 06, 2016 10:56 am

Don't take Summit's application listings too seriously. They only input what the manufacturer tells them when they start carrying the part, and the part was probably originally designed for a MC. If you contacted the manufacturer and they told you it would work, that trumps Summit's application chart. Seen it before.

by Silentknight85 Mon Jun 06, 2016 11:17 am

That's how I figured it. Just trying to be extra careful. Thanks!

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