Best mpg for 200 i6 manual 1966 mustang

Hey, I am new to this community. I just purchased a 1966 mustang with an I6 and manual transmission and was wondering what the best mpg I could expect if I switched from a carburetor to an EFI injection system and electronically ignition. Also, is this enough to improve mileage or can I do more. I intend to take this car on road trips and daily driving my driving is very conservative and the previous owner rebuilt the motor less than a year ago. Any other modifications you suggest would be a big help.
 

bubba22349

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Welcome to the Ford Six forum! Your post is in the wrong forum this all depends on the engine your working with, I can move it for you. I ask because a factory stock 1966 with a I6 would have been a 200 six, pictures will tell the tale. a 1966 Ford Mustang 200 Six example is in the below picture. Best of luck
 

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bubba22349

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Ok you post thread is now in the Ford Small six forum and many more of our site members will be able see it and respond to your questions. Good luck
 

DoctorC

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I've heard of 20's in this forum. 22 MPG was the max I remember seeing
-DrC
 

B RON CO

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Hi, my Ford six is in a Bronco so I can't help with MPG.
I suggest you enjoy the car and make sure it is safe and reliable before making major changes. You may decide you like it the way t is.
The cost of the parts may mean many years of driving before you see any financial advantage to the swap.
Personally, I like my changes from stock to be what the guy in the 60's would do, meaning no modern electronics, just what was available back then, but that is what I grew up with.
It is your car and you should upgrade as you like. I hope you hear from others who went with Sniper or whatever company, and I hope those products are as good as I hear they are.
Good luck
 

Lazy JW

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A carefully tuned carburetor will deliver fuel mileage equal to or better than EFI.

A poorly tuned carburetor, not so much.
 

escaper

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I get 23.5 on my i6 with Autolite 1100. Checked yesterday on the way to a show. I am planning on going the EFI route this winter though. Should also mention I also did a T5 upgrade. I think that upgrade was probably the best upgrade I've done to date.
 
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bubba22349

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Here is another comparison for you. This is a post by site member "Charlie Cheap said", "for my 65 Mustang. The OEM 200 had to be bored .060" over to clean up...which is not a good idea. I drove it to Tennessee last summer for the M6A show, running 75 and sometimes better just to stay with traffic. It had no problems running up to and above those speeds. After the M6A show we went to Mississippi to visit relatives. It ran great, got 24.5 MPG running the AC all the way, but refused to start after stopped, unless we allowed it to cool. Mine is built for highway running not max power. I will remove the internal goodies to put on this motor as I am well pleased with its performance. Anyone else needed a .060" bore and finding the same problem? It works but has issues with cylinder-wall flex when hot. Hoping a .030" bore will clean up cylinders but have a question. My 65 has 8.8 - 1 compression with 13cc dish pistons. The 73 looks like it has a lower compression when checking info pages. Is this true? Are the 6.5cc pistons the way to go? About 9-1 or 8.5-1 seems like a good road static-compression for a car not racing. With my cam that comes to just below 8-1 dynamic-compression. My dizzy is one I built with BWD SELECT parts and Pertronix conversion with a dual-advance (swing-weights-vacuum) modified with the 925D spring, manifold vacuum and Ford 9mm wire wound plug wires feeding Autolite AP46 plugs gaped at .040". A MSD .8 ohm ignition resistor puts a little more primary voltage to the ACCEL 42,000 volts coil, while the lowest ohms wires reduce that voltage as little as possible. With higher input the coil puts a little more to the plugs plus it has about 10K higher ability than the OEM. Better coil, more primary volts, Pertronix, the best available parts, tuned right, and platinum plugs...works." [image]img1743[/image]

These Falcon Six engines were well know for getting great MPG back in the day (Mobil Economy Run). So there you go mid 20's without much effort and I am sure if you worked at the combo's tune you could get much higher yet to around 27 MPG or so. Good luck
 

escaper

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For road trips you might improve your mileage more with a T5 swap as opposed to injection and have better performance and driving experience. For maybe about the same cost as injection you will have a close ratio four speed with a fifth gear overdrive.
With my T5 upgrade, I was right at 2600 RPM at 80 MPH on a level highway.
 

TrickSix

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Back in the 70s when gas prices spiked I put a new Holley "Economaster" carb on my 1966 200/C4 Mustang for a while. It was basically just a 1904, I suppose it had smaller jets or something, but ran good. With favorable winds and nearly legal speeds I got 26 mpg on the highway. That wasn't much better than the 1100, but I thought the world was going to end when gas prices hit 75 cents a gallon!
 

bubba22349

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Yes those were the days, and it looks like the fuel prices are heading up quickly again.
 

chad

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remember member "MPGs"?
What did he get pre 2v direct mount and the several bronco buys?
 
Hey, I am new to this community. I just purchased a 1966 mustang with an I6 and manual transmission and was wondering what the best mpg I could expect if I switched from a carburetor to an EFI injection system and electronically ignition. Also, is this enough to improve mileage or can I do more. I intend to take this car on road trips and daily driving my driving is very conservative and the previous owner rebuilt the motor less than a year ago. Any other modifications you suggest would be a big help.
back in college My 66 with a 200 and the 3.03 full syncro trans - everything else stock and everything maintained pre-internet days, tuned up right mine would run down the highway at 65 or so OK and I'd get about 26 mpg. No AC. Its tired now and dangerous to drive. No acceleration, but no blow-by. 130,000 miles on an engine that was rebuilt after the first 115,000 were rolled onto it.
 

chad

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just after a few yrs MPG (Member) & his milage posts are not in the Search?
What am I doing wrong~

I know that's carbed & Q is abt sniper but wanted to give him a base (as it might request). Well, seems
we already got that anyway (22 - 25 depending). Now sir, ah, er, um, Sid...got to our forum for the induction U seek & ask what they get there:

we don't buy them for milage, we tinker to modify that tho (performance = mpg and pep).
 
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Alastairq

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My 200 six, in a '67 Mustang coop, returns around the mid-20s mpgs. It has a holley{? no real markings, came with the car]...single choke carb, no PCV..and the engine runs well now I've got rid of the all vacuum distributor [mismatch not spotted by previous owners?]...and replaced it with a cheap, small cap TSP distributor, because it was the cheapest option here in the UK. [Fuel is currently around $8.80 an imperial gallon here where I live , E10 !] Automatic C4 trans...suits me down to the ground, nice to drive for an auldfahrt driver who drove for a living..now a not-work! Currently frantically repairing holes in the exhaust, as cannot afford to have new one made, or import standard one from US.. HAve welder, hate lying down on cold concrete.
 
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