Can a stock computer on 94 95 Gt hold tunes for h/c/I


Jun 30, 2021
Just trying to figure out what I need to do from when I do engine modifications for my mustang. I would like to do a explorer heads and intake swap with the gt40 heads not the gt40p because of the spark pug angle. For a cam I pan on getting something mild and was looking at the summit racing e303+ cam (different than the ford e303) but would love to hear other cheap and drivable cams.

With these mods I have heard that I need a tune and also that the stock computers are finicky. Can I get my stock computer tuned to work with the mods I want? Or should I get a different computer? Was looking at one of the mega squirt computers because they can plug directly into the stock harness. Any thoughts or should I look at another aftermarket management system.

Also on a side note does anyone know for a mild cam what springs should I use with the gt40 heads, can I use the stock Ho springs from the 7e head from the mustang motor, what spring rate should I look for with a mild cam, and do I need different rockers?

Lots of questions hope I posted this in the right section of the form as well.
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Mod Dude
Apr 6, 2011
Hillsborough county
Some of these questions are tuning related and I can answer to the best of my knowledge.

I need to know what year vehicle you are working with.
I tune Megasquirt systems all the time and so that is my go to, others may tell you that X system is the way to go because that is what they are familiar with.

What system are you looking at? there are at least 4 well known megasquirt systems for the 60 pin ford


Jun 30, 2021
Hi I have no need for a tune right at the time being just wanted to know what people on the form would say before I do something like h/c/I. I have a 1994 v6 that I swapped to be exactly like the stock 5.0 manual Gt. No mods to it now besides exhaust.

As for what mega squirt I was looking at was I think the Gen 2 plug and play or what ever option is cheapest but keeps nice stock things like air bags ac ect.

But if people have had success with the stock t4mo computer and tuning it with a chip or something that might be better for price.


Active Member
Dec 17, 2021
In your instance I would just go with specs of the engine that would work with a stock computer thats has the best tune and be more practical if you dont want to spend atleast another grand getting the car up to par with the setup being out of the norm.

What I can never understand is why they would put aluminum heads on an engine under 10:1 compression or supercharged is beyond me as Aluminum pulls heat away from the combustion chamber which reduces a complete burn..Think why they call Explorers -Exploders...Its not just the transmission....LOL
Screenshot 2022-11-23 165006.jpg

Just taking your stock setup and adding an adjustable valvetrain with 1.8 ratio rocker arms and angle milling the intake and stock heads to bump up compression above 9.5:1 and increase powrer 2 fold plus you can make some sick power with the same camshaft and ported stock intake...

Back in the days they would take a stock 5.0 and put stock style 1.7 ratio rocker arms , MAC Tune Shorty hedders w/ a Catback exhaust,better flow intake with a lil portwork plus an octane rod installed inside the distributor and 255lph fuelpump and made some pretty sweet streetable power that can be dialed in with a handheld tuner and yielded the same power youre gonna make with the setup you have thats gonna cost you more money than youre looking to spend to get it running right...

That is Unless you know someone with a Star tool with re-Flash cable adapter that can change the parameters in the ECU with a special chip inserted into that tool...The myth to the heavy doses of UV light needed to erase and reprogram an internal ECU chip are just that...Myths.....LOL

Theres also techs that offer ECU reflashing and they even come to your home ....The cool ones can reprogram too if you have the data for the changes.............
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Word through the grapevine told me recently that Moates has stopped making/selling and servicing tuning chips as they are retiring so the only option is the adapter board and a Megasquirt system.

Id never go Terminator X...The system is pretty bogus for anything but a racecar that blazes the track in short intervals.

The system is not smart and goes by the parameters of the sensors and for the money arent very accurate...They should be like 1/3 the price.

My expensive $125.00 Holley sensor for the fuel Pressure and the $125.00 sensor for the oil pressure were off by 12lbs on one sensor and 9 lbs on the other and I know theres a way to offset the difference but two weeks later when the weather temps dropped by over 10 degrees the sensors needed to be recalibrated once again so I went with cheap chinese sensors and they worked way better ..

And if you dont go with a TFI distributor and go with a magnetic pickup type or dual sync or hyperspark distributor your injection system will be a BatchFire system and not SEFI......!

Where are those facts on the list below?...Uhhh....I believe there is none....

Screenshot 2021-01-09 153341.png

The internal MAP sucks too..With -24 inches of mercury the lil blue tube was collapsing... I had to get an external 1 bar MAP and use that too.


Then to mention that I ordered 36lb Holley injectors and in the box labeled 36lb injectors #522-368 unknowingly inside that box came 120lb low impedience injectors which I installed them in haste then chose Holley 36lb high impedience injectors and even though Holleys manual states you must choose the correct injector and enter the correct injector values also they state that low impedience injectors wont run on a Term X system but the wrong impedience injectors did indeed run and they ran on the wrong setting too.


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I had to cut all maps by 2/3's to get my truck to run as good as they say will run with a base map and whats funny is no expert tuner could figure out the issue looking at my datalogs and even the ones I paid were just as stumped as the generous tuner guys who took time out of their tuning schedules to try and get me ironed out for free but in the end I figured it out the hard way what the issue was when my 8qt oilpan was full of fuel from the excessive powershots of fuel that entered my cylinders in the 3.5 seconds of fuel prime that was recommended by Holley and was used.........


Those extra unused LED's should of been on a chip that verified the proper injectors on one extra LED and the proper sensors with correct info is entered for the setup or give a red , yellow or green at both LEDS but Holley wasnt smart enough to think of that and left two LEDS that do nothing and labeled for future use..


After I got on the phone and raised hell with them and Summit Holley made good on replacing the injectors but when I sent another email that stated my engine along with picture proof was ruined from the gaswashing it received and I got a "sorry for your luck" email and they offered to give me 10% off as an insult to the thousands of dollars in ruined parts I had on my hands due to their bogus system and misboxed fuel injectors so I decided to bash Holley badly which people made me out to be the bad guy and wanted my head on a stick when Im the victim of poor quality and misleading info also predatory tuners promising me a resolution for $450 but tuners just as good as them couldnt figure it out for free as they said theyll help me because they like a challenge.. .......LOL

Had the system do what it said it wont do and thats run with low impedience injectors or run them on the wrong setting too then I wouldnt of ruined my engine if the Term X system couldnt operate as I would of found the issue sooner especially if the system was as smart as they claim and alerted me to the injector error.....

And before anyone says that with 120lb injectors my truck it wouldnt of even ran....Look at the picture of the screen////.Everything seems to look like its on par but it really wasnt.........I have a vid of it running too..It Idled smooth all day until I cracked the butterfly and released it....LOL

Oh and dont get me started about Holleys Limp Home Mode where it sets the idle at 2000 rpm's and having a brand spanking new TKO600.......


Good Luck figuring a solution you'll be happy with.............
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Jun 30, 2021
I thought they were called explorers because the transmissions and before that because of tire blowouts. Also the gt40 and gt40p heads from the explorers were cast iron but you could buy aluminum ones from ford. As for finding a stock computer that would fit my tune I don’t know if I could find any computer that is ob1 and better than the 94 gt one I have. I will look into places that can reflash them as that might be the cheapest. Also based on your problems with holly systems I might avoid them (also because they are expensive). I will keep looking for my options before I get modifying it.


I have been doing it wrong this whole time
15 Year Member
Mar 23, 2007
Middle of Maine
What I can never understand is why they would put aluminum heads on an engine under 10:1 compression or supercharged is beyond me as Aluminum pulls heat away from the combustion chamber which reduces a complete burn..
Just stop.
You have no idea what you are talking about
Aluminum heads will ALWAYS make more power than cast iron heads, all things being equal.
Not to mention the 50 lb weight reduction...
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Jun 30, 2021
I can understand the different expansion rates they have can cause problems like the head gasket failures on the 3.8 mustangs but when done right I think they are just better for the weight reduction benefits


5 Year Member
Jun 13, 2006
Columbus, Ohio
I have one of those Plug and Play 94/95 Mustang Megasquirt systems for sale. I'm not going to use it. Still brand new in the box. Also have an Autometer wideband O2 gauge and sensor as well as a brand new laptop computer to run it that has the software licenses to tune it.

Not trying to derail your thread but I'd like to not have this sitting on my shelf doing nothing.