[1978 T/A]

I am redoing my fuel system. I had the RobbMc 1/2 pickup but I decided that I want to get a new tank sump it.

I upgraded my RobbMc 550hp pump to the 1100hp pump with deadhead regulator and VR line. I am going to see how a deadhead fairs in Houston's hot summers.

My question is that if I do decide to run an electric pump with return later how are you guys plumbing the return line to the factory tank with sump? I would ideally like to run a 10AN return line.

[Skip Fix]

Karl when I sumped the Camaro's tank I had them weld on a 1/2" NPT bung for a return line where it would not be too close to any exhaust. I have a Jeg's sump I'll give you if you want it.

My TA has done OK with a non sumped tank but has a Mallory 140 electric deadheaded

[Cliff R]

I ran my Mallory 140 pump "dead-head" for a while before installing a return system for it.

It did OK, but the pump worked hard enough that it burned up the brushes while still under warranty. I bought another pump and plumbed in a return system while the first pump was getting rebuilt/replaced by Mallory.

The second pump ran flawlessly for over 10 years before burning up the brushes last summer. About 20 minutes on the bench and a new set of brushes and it's good as new.

The first pump only lasted a couple of months and maybe 1000 street miles "dead head". The second pump lasted over 12 years, over 1000 track runs, and many thousands of street miles.

Do the math on that deal when you make a decision as how to proceed with your fuel delivery system.......Cliff

[oville]

Is there a reason to switch to the electric vs run the 1100hp RobMC setup? putting together a motor now & will be right at around 520-540hp. Is the high hp mechanical pump harder on the cam? costing hp vs electric?

[1978 T/A]

The advantage to the electric unit with a return system system is it keeps the fuel cooler. Being that I am in the south vapor lock associated with a deadhead system could be a problem. But then again it might not cause me issues.

I already had the mechanical pump so I figured I would just upgrade it and buy the regulator. If I decide I want to switch an electric pump it wouldn't be that big of a deal to convert the regulator to a return style and sell the pump.

Skip I might have to take you up on that offer. Does the sump have the 1/2 fittings?

[oville]

Did not think about this till chating with Dave at SD (very nice guy), but its a lot easier to push the fuel from the back of the car vs pull it forward with mechanical pump when drag racing. Harder the launch & faster the car the more sense it makes to go electric. He also talked about running the same return line diameter as the feed line.

Cliff did you bend all new line for feed and return lines from pump to motor? and just braided prior to the engine to let it move around?

[68GoatMan]

I'm replacing my tank and line and I'm considering replacing my jacked up hard line with -8 AN teflon steelbraid aeroquip from tank to pump. Bad idea?
My pump is an Edelbrock Performer RPM Street (supposed 600HP capable), thinking about going with a Rob MC pickup.

99% street usage; 450-500HP

[66bonne]

FWIW: I run the RobbMc 1100 deadhead with regulator in scalding hot Florida heat.
I've never had any fuel associated problems on the street or the track.

Jim

[1978 T/A]

68Goat; Ideally you would want as much hard line as possible. But many members on this board are running braided lines. I don't really see a problem doing it as long as it is tucked up and secure. I am going to do the same thing as you. I had bought a pre-bent 1/2 fuel line, but I have no way of installing it unless I want to pull the body off the frame.

[1978 T/A]

Originally Posted by 66bonne

FWIW: I run the RobbMc 1100 deadhead with regulator in scalding hot Florida heat.
I've never had any fuel associated problems on the street or the track.

Jim

Glad to hear you have had good luck with it Jim. I figured it might or might not be an issue.
I like the idea of having a mechanical pump for simplicity purposes, so if it doesn't give me issues it will stay.

[68GoatMan]

Originally Posted by 1978 T/A

68Goat; Ideally you would want as much hard line as possible. But many members on this board are running braided lines. I don't really see a problem doing it as long as it is tucked up and secure. I am going to do the same thing as you. I had bought a pre-bent 1/2 fuel line, but I have no way of installing it unless I want to pull the body off the frame.

That's exactly why I'm think I'll run the flex line.

[HWYSTR455]

Using an AN 10 return line is just a plain rediculous. You should never have to run a return larger than the feed, for one, and many fuel companies even recommend one size smaller return than feed. Using a 1/2 feed and a 3/8 return is plenty. Unless you're using like a 3000GPH pump!

You can snake a fuel line in on a 68-72 A-body, without removing the body, it's just not fun. The worst part is removing the one line clamp bolt that sits on top of the rail, but it can be done. If you wanted to make it easier, you can clip the line where it straightens out and starts running the length of the frame rail, and just use some compression AN fittings, with a short piece of AN 8. Running the line is easier with the tank out and the one spring removed, but you can still do it without taking those steps.

You can use the original 3/8 feed line for a return if you sump the tank. If you have a RobbMC pickup, it has provisions for both feed and return, if you don't sump.

OE style gas tanks are so cheap now that it's not worth trying to get one cleaned out before sumping. You can even sell the old one if you want, get a few bux.

Also, there are EFI tanks with provisions for an internal pump, and you can run a carb type pump. There's already a sump in those tanks, and looks factory from under the car.

You can run braided line the full length of the car, but wow, what a waste. There's a weight factor too, as well as having to replace it every X years if you want to remain safety compliant. Not to mention it's even more difficult to run over the rear, it's bigger! And toss an AN end on there, bigger yet!

.

[Skip Fix]

Two 1/2" NPT holes on the sump.

I think using a Holley/Demon a mechanical will work easier. A small bowl Qjet starts getting tougher.

[1978 T/A]

Originally Posted by HWYSTR455

Using an AN 10 return line is just a plain rediculous. You should never have to run a return larger than the feed, for one, and many fuel companies even recommend one size smaller return than feed. Using a 1/2 feed and a 3/8 return is plenty. Unless you're using like a 3000GPH pump!

You can snake a fuel line in on a 68-72 A-body, without removing the body, it's just not fun. The worst part is removing the one line clamp bolt that sits on top of the rail, but it can be done. If you wanted to make it easier, you can clip the line where it straightens out and starts running the length of the frame rail, and just use some compression AN fittings, with a short piece of AN 8. Running the line is easier with the tank out and the one spring removed, but you can still do it without taking those steps.

You can use the original 3/8 feed line for a return if you sump the tank. If you have a RobbMC pickup, it has provisions for both feed and return, if you don't sump.

OE style gas tanks are so cheap now that it's not worth trying to get one cleaned out before sumping. You can even sell the old one if you want, get a few bux.

Also, there are EFI tanks with provisions for an internal pump, and you can run a carb type pump. There's already a sump in those tanks, and looks factory from under the car.

You can run braided line the full length of the car, but wow, what a waste. There's a weight factor too, as well as having to replace it every X years if you want to remain safety compliant. Not to mention it's even more difficult to run over the rear, it's bigger! And toss an AN end on there, bigger yet!

.

Removing the factory line was a PITA. I had to cut it out.

I am going to buy a new tank and sump it. I was wanted to know if there was any additional fittings should I decide to go electric down the road. Looks like I will have to have a plug welded somewhere near the top. Better do it now than later.

[1978 T/A]

Skip; If you're not using that sump I'll gladly give it a new home

[HWYSTR455]

Originally Posted by 1978 T/A

Removing the factory line was a PITA. I had to cut it out.

I am going to buy a new tank and sump it. I was wanted to know if there was any additional fittings should I decide to go electric down the road. Looks like I will have to have a plug welded somewhere near the top. Better do it now than later.

And this is the 69 A body? Cutting it out is the fastest way, curious where you had to struggle? Like the part where it goes over the rear? What are the body bushings like? Are they sandwiched?

If you sump it, you can use the OE feed lines as a return down the road. So no need to weld a bung or anything.

Are you on a hard budget? Can you swing an aftermarket tank? Do you ever think you might consider EFI in the future? Maybe consider alternatives to the legacy-type sumps. Placement is key, and they are suceptable to slosh, especially at levels below 1/2 tank.

Have you looked at the Fuel Safe in tank sumps?

.

[CROCIE JR]

Gotta use a return system in Texas. Perculation point of our fuel is 147 deg. F. I have not done a fuel sys. here without some sort of return. The best reg. around for the money is the Mallory 4309, coupled with the Carter 4601 or the Holley HP 150. You can get the Mallory Comp 140 with the 4309 as a combo. The Carter and the Holley seem to eat dirt better. Like a AK Vs. M-16. The factory 5/16" Vapor/Return is only good down to 6.5Psi with these pumps. Got to go to 3/8" to get full control of the fuel. If running no strainer, put a 100 micron pre filter. Kinsler has a good illustration of where to put the return. Basicaly, away from the pick up and deep into the fuel and turned toward a tank wall. I use 30 durometer rubber flange mounts if noise is a problem, from Mcmaster Carr. IMO dont even try it with a mechanical and no type of return. Even the vapor return with a Holley jet (.070") in it. Most of my return rails have fuel at the opposite end of the return.

[1978 T/A]

It's been awhile since I took the line out but from what I can remember it was a pain where it made an elbow from the tank to the frame in the back. Car was on original suspension, but that has all been changed since then.

An aftermarket tank isn't in my budget. I've got college to pay for. EFI would be nice, but I don't plan to do anything more with this car until I'm done with school.

I am going to give the mechanical pump a shot since I already have it. Wouldn't be too much work to switch it for an electric pump down the road. Do you have a link to the Kinsler illustration?

Also after I get the tank welded do I have to put any kind of coating in it?

[Cliff R]

Pushing the fuel from behind the tank is ALWAYS a better deal than trying to "pull" fuel nearly 14' with a mechanical pump. The lines need to be larger and all items before the pump free-flowing to keep up with big power.

I use the small factory return line and 8AN feed lines with a Comp 140 pump behind the tank and 8AN lines/fittings everywhere. I even tried using the factory 3/8" feed line from the regulator to the q-jet and stock q-jet filter and it worked just fine. Typically I will install an 8AN line from the regulator to the carb just to give me a "warm and fuzzy" on race days.

For a return set-up, I use a standard Holley regulator, with a 3/8" NPT "T" on the feed side. I come off the "T" with a 90 degree 3/8" x 5/16" inverted flare fitting to the stock 5/16" return line. A shut off valve is installed to "dead head" on race days, but I've never had to use it. The return system takes some load off the pump and keeps some fuel in circulation.

At full throttle the fuel takes the least path of resistance and easily keeps up running low 11's around 120MPH........Cliff

[Skip Fix]

Karl Merry Christmas

I could swear my factory return line on the TAs is only 1/4" not 5/16". And it just dumps in the top of the tank.