Hi guys, this is all about my budget EFI conversion I completed about 9 months ago. Perhaps I could have posted sooner. However, I wanted to make certain the system was performing rock solid before posting a "how to" thread.

this is my engine today.

And this is how she looked 1 year ago.

This all began as about 2 year's prior, I had done a freshening up of the engine. New heads, new cam, pistons and so on. Needless to say, my trusty old Holley that I installed some 18 years back was now out of adjustment. I no more than got the last bolt tightened up on the engine and my life fell apart. (Divorce was just finalised). Sooo, the car sat for awhile.
now to begin, I work with fuel injected motorcycles for a living, and I started thinking if I could get a wide band O2 sensor in one of the pipes, I could potentially get this almost 20 year old Holley dialed in. And then I thought, I have owned this car for over 30 years and have never had the fuel tank out. Never checked the rubber line's from the top of the tank to the steel lines. And those return springs that once were chrome.

So, the more I thought about it, the more I thought I needed to update the entire fuel system. In hopes of better running and better fuel economy.

So one evening I drew up this. No I'm no artist. But this is exactly what I did.

 

So step one. You need to get 58 - 60 PSI of fuel pressure to the throttle body. There are basically 3 ways to accomplish this. A fuel sump system, a external electric fuel pump, and a internal (in tank) electric fuel pump.
the first system that I know many use. I went past for the following reasons, one, as I mentioned earlier, this is a budget system, two, I would still be using my 43 year old pump and fuel lines to fill the sump. Also running 2 fuel pumps doesn't seem quite right to me. Finding a place to properly mount said sump system, and still needing to run a return line.
the second idea, and yes some guys have good success with is running a external electric pump.
Electric fuel pumps are pushers, not pullers . So if you have a bottom fitting on your tank and the pump is mounted below the tank. This can work. I have a 77 with a bladder in the tank. No bottom fitting.
3rd option, in tank pump. Most of you may have noticed that all new vehicles use this system. Runs the pump cooler and quieter.


My factory sending unit. If you look closely you will see in this photo that I have rewelded the sending unit guard. I found it in the bottom of the tank. I wonder how many years ago it came off. It's on there to prevent the bladder from contacting the sending unit float.
So yes out came the fuel tank, very straightforward. I ran her down pretty low on fuel first. And read a few threads on this forum as to how. Once out I found those 43 year old rubber fuel lines and vent lines in very good condition.



O.K. so I made up this. 5/16th's threaded rod. I welded a section of Harley exhaust clamp to the rod approximately 3 inches from the bottom as a saddle bracket for the pump. On the very bottom is a bracket made for attaching a furniture leg to a small table, has a 5/16th's threaded nut in the center, this will press firmly in the baffle in the bottom of the tank. The downwards pressure and the fact my baffle pan is on a rubberized floor will hold it in place. If you look at the first photo of the standard sending unit and compare with following photos, you can see I cut the stock feed line just above the 90 degree bend. The original feed line is now the return line. The original return line now has the pump power wire going through it and is sealed with JB Weld. A new bulkhead fitting has been installed for the new high pressure feed line. A through the lid, (properly sealed) fitting for the ground wire has also been installed. The threaded rod was sealed with brake line banjo bolt seals. After the rod was adjusted to the correct height to get firm pressure on my fuel baffle, it was cut off flush with the top nut so rubber cover around fuel cap still fit nicely. Also note proper intank high pressure fuel line from pump to bulkhead fitting. These are sold by Holley in many different lengths. Also the same as we run in Harley tanks.

Top view of my modified sending unit.

My Homemade fuel tank baffle. When assembled, the pump and pickup sock are on the end closest to the bottom of the photo and the return line returns into this pan.

Put a bit of fuel proof sealer on the old bladder just to be certain.

Top view of tank almost ready to go back in. New bulk head fitting top right, ready for AN-6 racing fuel line. Old fuel feed fitting, now return fitting with std. 3/8th's fuel line. Fuel pump power wire coming out of the old return fitting, ground wire terminal hiding behind the new return line just below the fuel guage sending unit wire terminal. Note vent lines. One from sending unit has a tip over safely valve and vents inside of bladder. One that go's to tank body, upper left, vents outside of bladder, so when you fill tank, any air between tank and bladder can exit. Allowing tank to completely fill. Small plastic line restrictor in body vent line just before tank fitting .(inside vent line). Prevents fuel backing into space between tank and bladder should any splash get into vent line.

 

So I reinstalled the tank with new lines routed just as the factory one's were. I added a wiring connector along side Factory sending unit connector. Over killed it amperage wise. And ran a ground wire directly to frame ground battery cable mount. Power wire through grommet with factory harness into back of storage area. And following factory harness into back of dash area.
O.K. we now have high pressure fuel delivery to the right rear fender well.
So , I decided to run a LS style filter/regulator to bring in the pressure to the desired 60 PSI. But how and where to mount it. Believe me I asked a lot of questions and finally came up with this.

I made up this bracket out of high strength steel. I drilled and tapped the frame. Very solid install.

So here it is all plumbed up. Note I wrapped the AN-6 racing fuel line with a short section of standard fuel line where the line go's past the number 4 body mount. It's fairly snug in there so vibration rubbing shouldn't be a problem. After 9 months and many miles. It still looking perfect.


so I next ran the new AN-6 racing fuel line right where the factory lines once ran. Being a flexible line I was able to fish it through at the front of the rear wheel arch. No body off frame. I used these vinyl coated clips to mount it along the frame, and used at least twice as many as the factory setup.
once to the front of the engine. I hot wired the pump and put my fuel pressure gauge on the end of the line. Perfect 60PSI pressure. No leaks and can't even hear the pump run. All this took me some time. But cost way less than a sump system. And so far the car looks totally stock. I might also add. Off came the 43 year old fuel pump, and on went a block off plate. Fuel delivery solved. Factory tank and bladder.

End view of the racing fuel line. Nylon wrapped on the outside, stainless wrapped under nylon, high quality vapor lock liner. 9 months of running, and my car is parked in a tight 1 car garage. No fuel smell. So far seems to be good value product.

 

Ok. So far I have shown how I got high pressure fuel delivery to a 77 corvette. You may not agree with everything I have done, and that's O.K. . I looked over the net before I started this. And I didn't find one system others did that I copied to a T. But rather, I got idea's from a number of different installs. And designed this. For the record, it works brilliantly. And can be used with any number of different fuel injection system's.

 

So, off comes the carb.


and on go's a Summit MAX 500 throttle body. In this photo I have the fuel line connected, PCV line and vacuum to the advance can hooked on. I might also add that the vacuum line that go's into the manifold at the rear of the carb/throttle body did not clear this throttle body. Fit fine with the Holley, wouldn't clear the throttle body. This was cause for a lot of running around looking for bits. I needed to plug the hole with something nearly flush and the vacuum fitting on the throttle body was much larger than the line and pointed in the wrong direction. Actually, it was the only surprise in the whole project. As I live in Australia, I ordered everything I needed in one order. This was the only thing I missed.

Auto parts stores proved worthless. Found this brass plug in a home hardware store.
next I needed an elbow to downsize the line and change direction. I was told by numerous auto parts stores this part does not exist. Didn't get my vacuum line done that weekend. Monday morning I dug through my tool box and found this.



perhaps not perfect, but it works perfectly.

Next I made this up. It's a store bought cable attachment pin made up with a spacer.


Next I drilled a hole in the linkage to put my pin as far out on the linkage as I could and still get full throttle with just a tad of slack. Didn't want the throttle to be to "touchy" . And as you can see I ran the cable inboard of the linkage. A bit of welding and grinding modifying a stock quadrajet cable bracket for a clean and tight cable install. And notice I got rid of those rusty return springs!

 

Well, we have a throttle body bolted down. And a throttle cable hooked up. But that won't make it run yet.

My old fan temp switch. Very basic system.

New CTS. (Coolant Temp sensor). but that old wire isn't going to connect to this.

Drilling a big hole in my exhaust system.

Nice big hole in my exhaust system.

New clamp on fitting and wideband O2 sensor. Keep in mind that the wiring connector for these things are about the size of a dog house. Keeping that hiden on a vintage car may be a concern. I have this one hidden behind the vertical chrome ignition wire shielding on the left side of the engine. Fairly tight in there but no one can see it.
O.K. new sensors installed. Ready to start wiring.

But where to put the ECU, finally decided to put it here at the base of the windshield.

A photo today with car assembled. Even with hood open and wipertray cover in place. No sign of it.

 

A couple more things to consider, air filter base fit properly on new throttle body, my valve cover to airfilter base hose is on the left side of the engine. Does it clear the throttle linkage O.K.? Air filter mounting stud will need to be remade. Have some 1/4-20 threaded rod on hand?? Some trial and error in getting that just right.

 

Now let me make it perfectly clear. Cutting up the wiring harness will void the warranty!!! Do not cut up the universal harness that does not fit!!!

Harness on right side of engine, extended and hooked up but yet to be tidyed up. Left rear injector wire had to be extended and CTS wire relocated and extended. All recovered with factory type nylon woven covering.

Hole drilled in firewall in wiper compartment on right hand side. Wiring going through here is wiring for the injectors, IAC, TPS and CTS

Engine side of firewall.

Drilling holes for left hand side wiring.

I ended up putting in 2 grommets on the left side. Here you can see 1fuse (One more slightly out of photo to the right). Wiring here is for switched power, battery power, ground, tach pickup, fuel pump power and wideband O2 sensor. Splitting the harness and running out 2 places really cleaned it up.

In this photo you can see an extra loop of wiring tied up to the upper edge of the wiper compartment firewall. This extra wiring is for the 02sensor. Remember that connector I said was the size of a dog house. I have placed it behind the vertical chrome ignition wire shielding. In order to unplug it for future possible service, one can undo this loop of wire, enabling you to pull the connector down out from behind the ign shielding and unplug it. No ones getting there hand in there with the engine in place.
mind you all the wiring was a very big job.and I have abbreviated it here a fair bit. But also your not supposed to cut the harness.
But these are the highlights.
How does it run?
Like driving a modern car in most ways. Runs fantastic. Fuel economy. Approximately 20 percent improvement.
Worth doing?
I doubt I have any more peak H.P. but driveability and fuel economy are much improved.
So, yes I really believe it was worth the time, effort and cost.

 

Nice work - one piece of advice if that braided line isn't PTFE based your going to want to swap it out. The old rubber stainless lines break down pretty quickly with fuel and your garage will smell like gas since it will start to "breath out" through the lines...

 

I like it. Nice and tidy. I would weld-in the O2 bungs .... allegedly they are really sensitive to air in-leakage; I welded mine on and then oxy-acetalyne brazed over that just to ensure no air back-in-leakage. On my EZ-EFI 2.0 adaptation I ended up cutting leads and extending others just to make things tidier...but I understand your concern.

 

Nice work and effort to keep it neat looking, ,,, your new throttle body injection will thank you in a large way if you now change out that 'ol duel plane manifold for a single plane,,, . . .

 

I am totally aware that cheap fuel line will indeed bleed through. Perhaps you missed the part that this was done almost a year ago now. Guy's with the fuel smell troubles using cheap AN hose notice this fuel smell problem within a couple months if not sooner. There are a lot of differences in fuel lines. Pays to do your homework. However, PTFE type hose isn't the only answer.

 

As per welding in the exhaust bung. These pipes are over 25years old now. Still holding up, but a bit banged up on the bottom. They do not want to come apart. So one day when I get rich I'll buy new pipes and weld in a bung. For now, it's working.
as per the single plane manifold. I have heard this before, and this one does need to come off soon to fix a oil leak. What would you recommend? And why? Car is running very well. thanks for your input.

 

Thought I'd update this old thread.
Here is what she looks like now a few years and a lot of tuning later.


Single plane early style Torker intake manifold, Custom curved DUI distributor, 2 1/2 inch ceramic coated exhaust manifolds and as you can see, a much larger airfilter.
Full 2 1/2 inch exhaust. Welded in the bung for the O2 sensor. Bumped up the compression and a few other little details.
to those who were concerned over my fuel line choice. Still working great, zero issues with fuel lines.
Lots of trial and error tuning but I got there in the end.
About 10K miles on it now. Purrs like a kitten and pulls like a train.

 

Great to hear the update. Glad your enjoying the setup.
You may recall, Im running FiTech, really enjoying it as well. Right out of the box, tuned itself well, no complaints. ( 4yrs running now). Sorry you had to do so much tuning. I love the simple cold starts, just turn the key, no need to warm up, just drive away if you want. AFR is always at optimal range.....
....ENJOY,,,🍷

 

Not necessarily. He is from across the pond so his fuel formulation may not break down non PTFE hose like a lot of places here in the US.

In short what nyciti is getting at is rubber fuel line isn’t compatible with fuels containing ethanol. The percentage determines the rate of decay. Some folks here in the US have no problems. Some of the rubber hose formulations are different as well but well over 1/2 the brands have issues. I live in the Washington DC area and it’s a problem if things haven’t been converted for it.