Engine swap fuel line routing/tech questions.


Founding Member
Apr 21, 2002
Pensacola FL

My son just swapped his 81 I-6 over to 88 HO.

One of our last obstacles is the fuel lines for EFI.

The donor car was a Lincoln Mark, so the fuel lines are:

A: Stock
B: Ancient
C: Ill fitting

So, what I need to know is a good way to either custom make fuel lines, or modify the parts I have to fit. I need to know what rubber line is acceptable for use, what clamps, and how to keep the hard lines where they mount to the fuel pump and fuel rails.

My son is a teen, so we are on a budget. We need a good way, a simple way, a safe way... We'd like to do it the 'best' way, but that is probably expensive.

Actually, the worst part of the Mark fuel lines are the plastic sections. The steel sections fit very well, but the longer car made for long sections of plastic. Fitting into the smaller car has made for tight bends, excess line, and even some crimps trying to form in the plastic.

Can I remove all the plastic sections and replace them with rubber?
What rubber line can handle the 40ish psi of the EFI system?
What clamps will work under that pressure?

I am generally a carb guy, but I figure that I can't just throw 5/16" rubber hose on here with worm gear clamps... Or can I?

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Founding Member
Apr 21, 2002
Pensacola FL
Fwiw, the swap has gone very well so far.
I tried modding the Mark wiring harness to work in the 81, but it was way over complex with many of the unneeded luxury/tech systems tied into the EFI harness, so we ended up file 13ing the Mark harness and got a ready made 88-93 Stang harness, just like Painless, but a different brand. Easy cheezy.

Since the wiring debacle, the son picked up an X-pipe exhaust, aftermarket headers, eliminator pullies, and he confiscated my Exploder intake that I had stashed for use "one day" on an undetermined project.

So now we are dealing with all the mods and put the wiring on hold till the end.

Yesterday I made plugs for the holes in the back of the heads, converted the larger Exploder TB to fit the Mustang style linkage/wiring harness, and did some modding to the GT 40 intake by drilling tapping holes, and tapping a pipe plug into the exhaust port originally ment fo the the EGR, which is eliminated in the wiring harness. Also modded his Mark intake tubing for the new MAF. The Mark was an early 88, and still on SD. The wiring kit is for a MAF system. So I picked up a 93 MAF at the u-pull for 25 bux.

WOULD YOU HAVE ONE? Auto trans...
The Mark ECM won't work with the new harness.
The u-pull gets 25 bux for an ECM, but 5.0 Stangs aren't really overflowing the u-pulls. :(


Founding Member
Apr 21, 2002
Pensacola FL
No one has any tips on rebuilding/updating fuel lines? :shrug:

We picked up a remanned ECM from Auto-Zone.

Personally I can't stand AZ, and go for Advance, as I have a commercial account there, but Advance gave me a big run around on getting the ECM, and wanted a $45 core. AZ was cheaper and no core.


Dec 5, 2008
Findlay, Ohio
I would use 3/8" brake lines for the feed for your fuel lines and 5/16" for the return. you can use the ready made sections of brake line and unions. They also make 50psi fuel injection rubber hose and specific fuel injection clamps. I would do it in a pinch like that. just route the lines away from heat, moving parts and rabid panda's. Use a good quality fuel injection rated fuel filter and go to town....


Founding Member
Apr 21, 2002
Pensacola FL
Just route the lines away from... ...rabid pandas.
I'll remember that... Those rabid pandas are always screwing up something!:nice:

So, I can possibly keep the very ends, front and rear, then build the 'centers' out of steel line... Then connect the stock ends to the custom lines with high pressure rubber line. ???

Sounds like a good idea as long as I find trustworthy clamps.
I have some brake line and tubing benders...

I'd like to keep the stock filter. It 'fell' right into place on the car and fits very well. I'll just have to figure a way to keep the stock filter connections. Otherwise I'll have to use a threaded filter off another EFI vehicle type.


Any other suggestions, tips to avoid pitfalls, etc... are welcome!


Founding Member
Apr 21, 2002
Pensacola FL

I see you run the Exploder intake.

We are using the HO, Mac headers, and 2.5" mandrel x exhaust, with 2.5" race bullets.

The engine was surprisingly stout in the Lincoln Mark when we bought it. What kind of increases are we going to get with these mods on a stock long block?

We are using the Exploder intake, Exploder TB (looked quite a bit larger), and a stock 55mm MAF.

I know the MAF is a bottleneck, but with all the EGR, AIR, A/C, and tiny 2" exhaust gone, I figure we still have made some healthy gains. The free flow mufflers alone should be good for 10 rwhp in my past experience.

With all the above mods, would you agree we might see as much as 25-30 rwhp?

What do stock SD HOs get for RWHP with AODs?

It's not my car, but I really am dying to hear it run with those Dynomax bullets...
I ran a single Dynomax 3" on my Z28 and it sounded gorgeous! Deep and mellow at idle, then pure NASCAR at WOT.
The big variable will be the dual exhaust thing. It might end up nasty loud. ???


Founding Member
Apr 21, 2002
Pensacola FL
One more GT40 intake question...

The aftermarket harness has built in eliminators for the EGR and such.
So I bolted the TB directly to the upper, no EGR block of any sort.
I tapped and pipe plugged the hole between the runners to keep any exhaust from getting to the upper.
I also plugged the holes in the back of the heads.

Are there any other holes, passages, internal plumbing that I need to consider?
I don't want any exhaust or heat flowing either open or around the incoming cool air.

The GT40 lower didn't have an intake air temp sensor, so I drilled and tapped the boss that matches the stock location on the original HO lower.

I am second guessing that now. That location will see more heat than some other options, and I want the car to run best for the temp of the incoming air.

If I move the sensor to the tube between the MAF and TB, the sensor will read a lower temp than stock. Am I right thinking that this location could cause the car to run rich? If so, the headers and free flow exhaust would tend to cause some cars to run lean, so it should even out???

Or is the stock computer just not that responsive as to make a difference?
(But then why would you need the sensor?)

I apologize for all the elementary questions... I am learning though! :)
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