To EFI or Not EFI, that, and which one, is the question.

[tony-muscle]

Its been a while and that little voice in my head is back telling me to try out some sort of EFI conversion. If I'm wanting to prioritize being able to roll the process back in the event that it doesn't work well or I can't get spare parts, what is the least invasive route?

I think a sniper style setup that mounts to a carburetor pattern lets you do EFI with the least amount of modifications to the engine. Where I'm stuck is the fuel system. It looks like all the options I've seen require replacing the whole tank, cutting a big hole in the top of the tank for a new drop in pump, or at the very least drilling a hole somewhere to install a bulkhead for the return line.

There doesn't look like enough room on the factory sending unit to install the return bulkhead.
I have seen people saying they install the return into the fuel filler neck. Thats in the trunk. From the factory, all the fuel in the trunk area is separate from the passenger compartment by steel. I'm not overly excited about the idea of running a high pressure rubber fuel line and adding in more fittings and gaskets that may eventually leak. Any fuel leak you created by adding a bulkhead to the filler neck would not be sealed away from the passenger compartment.

How else are guys handling the return lines? Short of running the holley "returnless" intank pump which requires cutting a huge hole in the tank anyways.

There are other options. I run a mechanical fuel pump that feeds the Robbmc Powersurge Pump (https://www.robbmcperformance.com/products/powersurge.html). This pump has a submerged electrical pump in what is about 1/2 gallon tank. I used the stock tank breather tube to the charcoal canister as a return. This involved getting rid of the charcoal canister, installing a new stock line just to make sure all is clean, opening the top tank vent return port and making sure the tank can breath through the gas cap.

https://7173mustangs.com/threads/ha...-fitech-pac-efi-unit.23975/page-4#post-294938

 

[giantpune]

There are other options. I run a mechanical fuel pump that feeds the Robbmc Powersurge Pump (https://www.robbmcperformance.com/products/powersurge.html). This pump has a submerged electrical pump in what is about 1/2 gallon tank. I used the stock tank breather tube to the charcoal canister as a return. This involved getting rid of the charcoal canister, installing a new stock line just to make sure all is clean, opening the top tank vent return port and making sure the tank can breath through the gas cap.

https://7173mustangs.com/threads/ha...-fitech-pac-efi-unit.23975/page-4#post-294938

I had considered using the factory vent line, but wasn't sure about what else was required. And does that prevent you from being able to use a pop open gas cap?

 

[tony-muscle]

I had considered using the factory vent line, but wasn't sure about what else was required. And does that prevent you from being able to use a pop open gas cap?

I suggest the vent line only for the Robbmc that needs limited return. However, I don't think it will be large enough for a standard electric pump. I have a pop open gas cap but I had to "tweak" the internal venting system so it is open all the time.

 

[Steve McMahan]

I actually did this tank mod on my Ford factory EFI swap. There are two pumps to choose from, one fir a carb, and one for a stock 40 PSI system. I did the 40 PSI pump and so far, it’s working great:

https://7173mustangs.com/threads/in-tank-fuel-pump.40147/
Kilgon does a great job explaining the tank retrofit.

 

[Captain Morgan]

Good timing for this thread to crop up. I was also thinking about it down the road. Deep in my soul, I’m a romantic so I’m not quite ready to give up the carb. I follow this kid on Youtube and he runs a pretty good channel. He has a 65 with a 289 and FiTech hooked him up with a FI system and he filmed the install and impressions.

 

[Dellguy1973]

Installed the Holley Sniper on my 73 convertible Q code this spring. My car was always hard to start cold (compared to my 68 289), and if I didn’t drive her for any length of time, she would also have stumbling issues off idle. I know these are all things that can be fixed, but sometimes I just wanted to get her out of the garage and go drive and not worry about all that stuff. The sniper has been awesome! Key in the ignition, wait for the pump to do its thing, turn the key, and she starts up immediately! Let her warm up a little and from there she’s just a joy to drive. I have it installed with no return fuel line but have had no issues with that. I had a small acceleration issue at first but plugged in the tuning device and had that sorted in 2 mins! My only complaint would be that the fuel pump is loud! I may have to deal with that at some point (if possible) but otherwise I am really glad I did the conversion.

 

[giantpune]

I have it installed with no return fuel line but have had no issues with that.

How did you do this? One of the holley retrofit in-tank pump?

 

[Dellguy1973]

How did you do this? One of the holley retrofit in-tank pump?

Was able to retrofit the Holley 65-70 in-tank pump. I was told mounting an exterior pump would be louder than the in-tank pump……and the in-tank pump is loud enough! But I’ll live with that for the benefit (for me personally) EFi has given me.

 

[Bobby]

I had many issues with my Edelbrock 750 CFM. hard to start and fuel draining out of the line to the pump. I have installed a Holley Sniper and a dual sync MSD/Holley distributor. New stainless fuel line and pressure hoses. Will finish this weekend and fire it up! I installed a Aeromotive gas tank with an integral in tank fuel pump.

 

[Bobby]

How did you do this? One of the holley retrofit in-tank pump?

To my knowledge, Holley pump will not fit in the vapor vent opening. Not enough clearance with the floor of the trunk unless you cut a hole for it. Aeromotive makes an electric fuel pump/sending unit that you can use in place of the original sending unit. Had I known that, I would not have bought the fuel tank/fuel pump combo! I only found out that Aeromotive sells it separately after the fact.

 

[giantpune]

Aeromotive makes an electric fuel pump/sending unit that you can use in place of the original sending unit. Had I known that, I would not have bought the fuel tank/fuel pump combo! I only found out that Aeromotive sells it separately after the fact.

I talked to the aeromotive tech guy on the phone. He said they basically offer 2 different products to handle the fuel pump situation on our cars. The $700 tank+pump+sending unit is the first one. You can see on the bottom it has electrical connection and fuel connections. But the pump and sending unit itself are installed in a separate hole at the top of the tank. The part down there that fits in the original sending unit's place is just the connections and not the pump and sending unit.

Their other product is "the phantom". Its a drop in fuel pump similar to the holley retrofit one. It involves taking an OEM tank and a hole saw to make a hole in the top to drop in their pump. You still retain your original sending unit when you use this.

I called them up specifically asking about what you described. Just a pump/sending unit that replaced our stock one. He said they dont have anything like that.

Also, how does the aeromotive product vent? Is there a provision somewhere for your stock vent to hook up?

 

[rcadd1ct]

I went with an Aeromotive stealth 340 tank. it has the pump in it and all the connections are via the stock sender area.

pretty easy install.

depending on which regulator you get you can convert back to carb.

the Aeromotive regulat or I bought has a swapable diaphragm for either carb or efi pressures.

I went with the term x stealth 4150 system so the ecu could be mounted in the passenger footwell.

I do have a new stock style tank I took out from a failed build that has a return bung welded in I have to sell.

About to list a bunch of stuff I have leftover from my build

 

[rmowrey]

How did you do this? One of the holley retrofit in-tank pump?

I bought a new tank for my '73 and installed the Holley intank pump in the top prior to installing it. I used the returnless style and capped the return line at the Holley Sniper. It's been working great for 5 years.

 

[Kilgon]

Several things to take into consideration when changing over to efi with electric fuel pump. First is the pump rating both psi and gph. Make sure that whatever pump you use will meet the specs needed for the efi. If you go with the Aeromotive fuel tank or their pump the 200 lph is plenty for our cars unless you have a high-performance engine. It is rated to handle up to 600 hp. I see no need to spend an extra $100 on the tank combo when you don't need to - but - it's your money so whatever floats your boat. Second, when switching over you SHOULD add an inertia switch in case of a collision. Need to remember that even if the engine isn't running the electric pump will continue to run until the key is turned off. Also, depending how you end up venting the tank you may need to add a roll over vent valve to keep gas from coming out of the vent line in a roll over crash. Hope this helps a little.

 

[giantpune]

Several things to take into consideration when changing over to efi with electric fuel pump. First is the pump rating both psi and gph. Make sure that whatever pump you use will meet the specs needed for the efi. If you go with the Aeromotive fuel tank or their pump the 200 lph is plenty for our cars unless you have a high-performance engine. It is rated to handle up to 600 hp. I see no need to spend an extra $100 on the tank combo when you don't need to - but - it's your money so whatever floats your boat. Second, when switching over you SHOULD add an inertia switch in case of a collision. Need to remember that even if the engine isn't running the electric pump will continue to run until the key is turned off. Also, depending how you end up venting the tank you may need to add a roll over vent valve to keep gas from coming out of the vent line in a roll over crash. Hope this helps a little.

If you go with the aeromotive full tank/pump/sending unit setup, does it have a vent or do you need to modify your gas cap somehow?

 

[Kilgon]

If you go with the aeromotive full tank/pump/sending unit setup, does it have a vent or do you need to modify your gas cap somehow?

It uses the vent tube on the car that runs to the charcoal canister. You do need to add a return line. Regardless of how you go you will need to make modifications of some type. Also, as I mentioned you should add an inertia switch for safety in the wiring going to the pump. I added one and it is located behind the drivers kick panel. I also added an inline switch to shut the pump off as a theft deterrent. Here are a couple of pictures of the inertia switch and the rocker switch to turn the pump off.

 

[giantpune]

It uses the vent tube on the car that runs to the charcoal canister. You do need to add a return line. Regardless of how you go you will need to make modifications of some type. Also, as I mentioned you should add an inertia switch for safety in the wiring going to the pump. I added one and it is located behind the drivers kick panel. I also added an inline switch to shut the pump off as a theft deterrent. Here are a couple of pictures of the inertia switch and the rocker switch to turn the pump off.

View attachment 77333View attachment 77334View attachment 77335

Ok, so it uses the factory vent setup coming out of the top of the tank and then you just worry about the 2 main fuel lines coming out and then back into the bottom of the tank?

 

[Kilgon]

Ok, so it uses the factory vent setup coming out of the top of the tank and then you just worry about the 2 main fuel lines coming out and then back into the bottom of the tank?

Correct. You could make a new fuel line going to the efi and then use your existing as the return since the return is low pressure. Edited - to clarified - since the return is low pressure you don't need to worry about the condition of your original fuel line unless extremely rusty.

 

[AcesArneson]

I am going with a hodge podge. Found an old Offenhauser intake that was previously ported, so I am going with SEFI. Also wanted a 4 speed automatic so I located a 2004 Crown Vic in the junkyard and took all of the wiring, EEC-V and tranny controls. The tranny I am using is a 4R70 from a 2004 mustang with a V6, had it rebuilt to take the torque of my Cleveland which is still in the shop (man Cleveland parts were hard to come by through the pandemic). Just waiting on the flexplate and it goes back together.

With SEFI you need a crank position synchronizer and a cam sensor. The guys at 460EFI can get you the wheel and sensor/mount. I had to go to Price Motorsports for the cam position sensor (Ford never made one for the Cleveland).
Got the fuel pump from a 2011 GT through Rock Auto then ordered all new fuel lines, check valve, pressure controller and pulsation dampener for the fuel rods that the mechanic is mounting for me on the Offenhauser. Deka shorty 80’s look like they will fit under the air cleaner.
My 73’ vert never had a NACA intake or hood so I got the whole kit and went with ProM racings ‘under the air cleaner’ MAF with an Edelbrock 800 CFM carb style throttle body.
The EEC-V is programmable so I ordered a Moats Quarterhorse so I can tune it in.
I think if I had to do it all again I might just buy the kit from the 460EFI guys. Pricey but would have saved me a ton of time looking around for stuff on the web and at junkyards.
https://460efiguys.com/product/351c-and-clevor-low-profile-efi-kit/

 

[Dellguy1973]

I bought a new tank for my '73 and installed the Holley intank pump in the top prior to installing it. I used the returnless style and capped the return line at the Holley Sniper. It's been working great for 5 years.

Exactly how I did mine. Used the original tank by dropping it down and installing the retrofit pump. Went without the return line. It’s been working great. And getting back to the original question or whether or not to Efi, I would say do it without hesitation it is definitely worth it!