Thanks for the info guys.

To the OP, I think this means that instead of a different fuel pump, on a 1968 327/300HP you should have the AC Delco vented fuel filter in your fuel supply line, with the vent connected to the return line that is capped in the picture. On my car, the filter is located about where your fuel line runs in front of the passenger side valve cover.

I think some of the other posters might be right about cost being a factor; the "correct" fuel filter is (I think) only available as a reproduction and cost north of $50!! The original is AC-Delco part number GF-432. I don't remember where I bought mine maybe Ecklers?

 

I fixed your post for you. Bubba will install these devices nonetheless.

 

Does anyone have a pic of a stock style fuel pump? Do they accept AN fitting?

 

Did all C3 corvette fuel pumps come with something to connect a return line? The 69-70 fuel pump only had one provision on the bottom of it for one fuel line is it to feed the carb or to return fuel to the tank? The fuel pump on the 70 LT-1 I believe is the same. This is why I wonder if a return line is necessary.

 

Nearly all the after market fuel pumps do not have provisions for a return line so the lines are blocked off.

 

Q-Jet equipped Chevys in 68 & 69 used the big can fuel filter, GF-432, which had the return line provision on the bottom.

1970+ (I'm fairly sure of the year) had the return line provision from the fuel pump. These pumps have three nipples on the bottom.

The return line was needed to prevent vapor lock. By looping cool fuel to and from the fuel tank, the liquid gasoline doesn't have time to vaporize in the fuel lines in the hot engine bay which caused cars to stall out, especially in places like here in Texas.

Holley equipped cars typically didn't have the return line provision. I'm guessing that fuel moved fast enough with a Holley (just a guess).

The return line has nothing to do with charcoal can and evac system as was stated earlier.

I'd run the return the line system if your Vette was so equipped. I usually yield to the engineering and R&D that went into the development of our Vettes.

But nothing says "Bubba" better than a bolt on the end of a fuel hose. Jeez.

 

I am glad you typed it because now I do not have to...thanks dark blue 454.
On another note, I have in the past, for SOME of my customers who do not worry about originality, installed fuel tanks with return line provision and a return line from later year models on their 63-67 Vettes so the possibility of vapor lock is removed when they drive around town when it is HOT.
Situations change and GM engineers have to make changes to off-set these new findings that they are dealt with throughout history. What was good back then may not be the way it is done today due to new information and design.
Often times keeping things as originally designed works great, but sometimes changes MAY need to take place to correct an issue that puts the operating systems in a state of extreme tolerances.
"DUB"

 

I have a 1982 with the electric fuel pump at the tank, which goes up to a factory fuel filter on the side of the frame. I blocked the return line and hooked the main line up to the carb. I never had the fuel injection, so I don't know where the return was hooked up to Org. Can anyone tell me, and should I hook it back up??? Thanks I appreciate, Gene

 

The return went to one of the throttle bodys.

 

My 69 vette has a similar set up. I did not do it, the PO did when he installed the 502 BB motor. I remember him telling me that an electric fuel pump was needed to install the 502.

I am not a fan of it and I would like to reverse it someday. Not a big fan of the 502 either. Sometime in the future, I want to build a 427 motor and put it in the car, although it will never be numbers matching.

 

So two lines going from tank to fuel pump and one line going from fuel pump to carb (which probably has in-carb filter) does mean that I have '69 setup on my '68 327/300? Thanks.

 

Actually, no. If your return line goes to the fuel pump, then you have a 1970 (or later) setup. If my understanding is correct, both the '68 and '69 small blocks with Rochester Quadrajet carbs had a single fuel delivery line running from the tank to the pump to the carb. In that (metal) line, between the pump and the carb, is located the large fuel filter, AC Delco part GF-432. The return line connects to this filter--not to the pump. I believe a couple of other posters said this as well.

If you have a later style pump with a return, that should function in the same way as locating the return at the filter. The Quadrajet does have a small filter, but I would install an in-line filter if it were me.

 

Becuase the return line is rotted out.

I have'nt used mine since I started upgrading everything, and now the return line is a crumbling mess

 

Here's a shot of the topside of the 68 small block fuel line set-up.
Small line is the return line to tank.

 

No, stock pumps have rubber with a hose clamp tubes into the pump body

 

I wonder how many psi you're hitting your replaced carb with.

 

Don't mean to hijack this thread,but I just built a 383 for my 77. would you use the stock pump with the return line or an aftermarket pump without?

 

doctorgene: I am a bit concerned about your car. I am very cautious when fuel systems are being altered. Mind you that I have not seen your car so please forgive me if I bring up issues that your car does not have wrong with it. But I am writing due to the years of seeing butchered fuel systems that bring the car to the point of being a "roman candle". I do not know your skill level so please excuse me if I seem to cover issues that you already know about. I just want to mention issues that can be helpful to you and others.
First off I am worried about that type of hose you are using to supply fuel to the carb. I hate rubber hoses that are under pressure in an area of vibration and heat. I prefer to have a hard steel line to go from the factory style pump to the carb like the factory. IF you have a rubber hose or even a stainless steel braided hose , just be sure to occasionally check it for it condition, (dry-rotting, cracks, getting hard, etc). Remember that it is under pressure and IF it goes bad, it will spray fuel in an area of heat and sparks. Along with the fan blowing air, while running, it causes the fuel to spray against your firewall and if it catches fire, and you DO NOT have a fire extinguisher, and have the "stones" to oper the hood and try to put it out....well you might as well get out the marshmallows and franks and have picnic. I have seen the end result of a bad fuel system that was neglected. It is not pretty....needless to say.
Also the fuel pressure to your carb is about 11psi+ when it should be about 7psi. It should be regulated via a fuel pressure regulator or have the sending uinit removed and install a sending unit from a 78-81 and install a factory style fuel pump on the engine block. This will give you a fuel return by using the 70-81 factory pump set-up.
Like what was earlier posted, your original fuel return came off of your throttle bodies.
I know it gets hot out there in Kansas and you MAY have a fuel vapor lock issue during the summer months while driving for extended periods of time. And then again...you may not. But the issue of non-regulated fuel pressure COULD cause you problems in the future if your needle/seat and float get damaged and fuel will shoot out of the bowl vent of the carb looking like "Old Faithful". I have seen this occur, even on mechanical factory pumps at much lower pressure than you are running right now.
Here is what I did on a 1978 for a customer who wanted an electric pump in the tank. I had to find a way to keep things safe and reliable. One thing led to another and it led me to a modified system that he was happy to do on his car.
I installed the VATS (vehicle anti-theft system) out of a 1986 Corvette, where the ignition key has the microchip installed to stop theft. I intergrated it to the crappy alarm system the 78 had and did it without a computer. It works just like a 1986+ alarm system. I installed the oil pressure cut off switch for the fuel pump so if the oil pressure gets low, or engine dies, the electric pump will shut off to protect the engine, even if the key is on. Just like what your car has now. I installed an electric fuel pump out of an 82 along with the sending unit. In installed a fuel pressure regulator and plumbed it into the pressure (supply) line going to the engine. I removed the factory fuel pump and removed the rod that the cam pushes to drive the fuel pump and performed a "trick" to the pump and re-installed it on the engine. When you look at the car , everything is original in appearance, except it has all the features of a 86 theft system, including a starter interrupt. The car will only crank with the correct value of chip in the key, and if you were to "hot wire " the starter, it would only run as far as the fuel in the carb would let it go due to the electric pump would be dis-abled. Using the factory pump it aslo has the fuel return working and the fuel pressure to the carb is perfect.
This was to let you know that it can be done and WORKS. Like earlier written, it all depends on you and your issues.
"DUB"

 

fantic,
I would use the stock pump with the fuel return. If the factory pumps were use for the 454's, they should work fine for your 383. But to each his/her own. Many engine builders / tuners like to pump as much fuel in the engine as possible. for some reason they feel more is better, which sometimes is true,but then there is also "overkill", especially when it is a driver for the street. A chassis dyno may help you out if you are looking for the maximum the engine will give you if you are like one of those guys/gals who have a "serious" engine in a daily driver....which I know you are out there.... just waiting to "chime" in with your views on what is working for you.
"DUB"

 

grandmastercorvette,
Let me use this opportunity to pick your brain as well.

My car has a 502 HT crate motor. The PO installed the new motor and a Holley electric fuel pump close to the tank. And of course he removed the return line and there are enough rubber hoses involved. I have been wanting to return the car back to almost stock condition. A few questions.

1) Will a stock fuel pump set up work with a 502 HT crate motor?
2) If not, are there other alternatives that resembles the stock set up?