Ford small six MPG swap questions

falcon_master

Well-known member
Hey everyone, another usual question here. One thing I love about our sixes is their light weight and decent fuel economy compared to there v8 brethren. I say decent because there still pretty low compared To modern sedans. Now I had a question for you all. Should I swap a 200 or a 250 into my car. I don’t really wanna hack up the radiator support that much because I want to be able to take the car back to original any time I want and have it look normal. My other problem is fuel economy. What do people usually get with a 250 or a 200. Online I’m seeing anywhere from 16-22 city for a 200 and 12-18 city for a 250. Highway miles don’t apply to me as I do not take the highway often at all so city is was matters to me. I know these aren’t amazing fuel sippers but it seems to me if a 250 is only getting 1-4 mpg better than a v8 might as well v8 swap it. And I feel like only 16-18 out of a 200 is pretty low. I eventually plan on doing a T5 and better rear gears. Just wanted what your guys average city numbers are with what set up and if I should do a 200 or 250. Thanks everyone
 
I can appreciate the concern for retaining the small block six' economy advantage. A quick reply would be that the 200 is an excellent performer and will slip right in to an early car with simple bolt-on adjustments. 200 has options more readily available than the 250 for both performance and economy upgrades with electronic ignition, better carbs etc , . The 250 in early cars requires substantial fabrication or modifications in my experience. In late 60's thru 70's, the 250 met the need to sustain Interstate speeds with high rear gears and have enough low end torque to rival V8's. But the 250 in OEM trim is not considered an economy alternative over a 200.

You mentioned a T5 , the revolution in OVERDRIVE in both standard and automatics in the 80's and computer management led to new approach to power application. I run Overdrive T5's in a 61 with a 250 and 3.80 rear gears for performance. DailyD' is a 63 with a 170- T5 and original 3.50 rear gears. 170 with a typical V8 T5 1:68 OD ratio the 170 and T5 can cruise at interstate speeds, carve back roads and gears with great mileage and fun.
 
The 200 is the same size as your 144, so fitment is not an issue. You will be able to use the motor mounts, radiator, and air cleaner from your 144. Hood clearance will be the same. Any 200 with the single or dual bell bolt pattern will allow you to use your flywheel, PP, clutch disc, and transmission (2.77) from your 144. If you want better performance/gas mileage change out the distributor with a recurved unit; you may have to change out the carburetor with the distributor if the 200 has a load-o-matic.

What rear gears does your Falcon have? With a 144, it probably has 3.55s or higher. The higher gears will make the 200 peppier in town, but your mileage will be lower than if you had 3.20s. A T-5 would definitely help with this.

Hope this helps.
 
Hi, a friend of mine had a 144 in a 62 Falcon that got 30 MPG highway driving. Good luck
 
falcon_master":doxcxk6w said:
Hey everyone, another usual question here. One thing I love about our sixes is their light weight and decent fuel economy compared to there v8 brethren. I say decent because there still pretty low compared To modern sedans. Now I had a question for you all. Should I swap a 200 or a 250 into my car. I don’t really wanna hack up the radiator support that much because I want to be able to take the car back to original any time I want and have it look normal. My other problem is fuel economy. What do people usually get with a 250 or a 200. Online I’m seeing anywhere from 16-22 city for a 200 and 12-18 city for a 250. Highway miles don’t apply to me as I do not take the highway often at all so city is was matters to me. I know these aren’t amazing fuel sippers but it seems to me if a 250 is only getting 1-4 mpg better than a v8 might as well v8 swap it. And I feel like only 16-18 out of a 200 is pretty low. I eventually plan on doing a T5 and better rear gears. Just wanted what your guys average city numbers are with what set up and if I should do a 200 or 250. Thanks everyone

X2 Well if the best city MPG is your goal than the smallest engine will give best economy. The 144’s were well know for their economy. Back in early 1971 I acquired a wrecked 1970 pinto (500 Miles) swapped its 1600 CC 4 cylinder Kent engine (also a high MPG engine) & four speed plus the rear axle into a 1962 Falcon for a MPG experiment. Good luck on the Falcon (y) :nod:
 
There is more to economy than just gas mileage. The cost of doing an engine swap is very large.
 
Thanks for the replies everyone. I am pretty sure my car has 3.10:1 rear gears. I will confirm later using my tachometer and measuring the turns it takes. I just wanted to know how much worse a 250 is over a 200 and is it worth the extra torque and power for all the mods and cutting and lost mpg to get it in
 
I think maybe some extra claification from you might help too. Are you wanting more performance or just more enconomy? if you wanting a little of both than the 200 would be best. IF you looking for straight performance id still say 200, the 250 is better but it a harder swap. Alternatively economy i think a 144 with a T-5 an a good rear gear would be adequate. You know what they say that the biggest factor as to your fuel economy is your foot, and if you are looking for economy are you ok with always being rather slow? Or if you want / like to keep up with traffic than were back to 200. A well setup 200 with a T-5 and either 3.25-3.55 8 inch would be a perfect setup for decent 100-125 hp performance and good economy 18-22mpg.
 
the i6 is not an MPGs mo-chine. Choose them for different reasons, enjoy them for that.
Pick up all the tips B4 any engine swap or drive line mods. There's several threads on it here and quite a few pointers in the Handbook (got one?). Also see member (is not around much these daze) "MPGs" & his work documented here.

Tire sz/choice/air pressure,
driving style (biggest)
breaking style (also big)
carb choice/tune
ign components/tune,
unsprung weight
motor oil'n lubes (inc well maint wheel bearings, & crankcase change)
motor choice to vehicle weight
transmission choice
(tailgate open/closed has shown to have lill effect in p/u but cap does) so
airodynamics (inc ac v windows)
PLEZ ADD More if ya gotem...
 
200 all the way man. It's literally a drop in for you. The carb and your dizzy should be all that you change.
I have a 3.03 manual, 200, 2.8 rear, Weber 32/36, uncurved HEI, and am getting an average of 18-20mpg. My buddy and i drove to Canada about 180 miles away and sat in Vancouver traffic for 2 hours, averaged a total of 25 MPG. Straight highway to Canada doing 70-75.

If i could run more timing like 12 BTDC without pinging i might consistantly get 20MPG. But the 2.8 is too much with a stick and all the hills. I can't wait for a T5 and 3.5+ rear gears.

Good luck man,
Ryan
 
Gearing requirements with a 3 speed are no lower numerically than a 3.45:1 axle with a 144.

I had a three speed 138 in line six with a 2.95/1.69/1:1 3 speed, and used a 3.9:1 axle it came with standard in 1958.

I then added a 4 speed close ratio gearbox and added the 3.45:1 axle .
 
If your 3 speed has a wide ratio set with a synchronized 1 st gear , then the overall first gear governs the final drive. For starting off on a 12 to 22% grade with less than 145 lb-ft at 2400 rpm, a 11:1 ratio will do it good enough.

With a 138 to 144 cube inch six in a 2500 pound car, then the first gear ratio can still be less than a smidgen lower numerically than a 11:1 overall first. For example, if first gear is 3.50:1, then you can slip in a 3.10:1 axle ratio, which, IIRC right, the early XK Falcon 144's were from factory, without a sychro on first gear.

If its got those simply nukking futts 4 cylinder T5 or Tremec 140/142 5 speed gearing the old 2.3 liter OHC Fox Fords ran from 1980 to 1988, then first gear is 4.01 or 3.97, and you can run a set of 2.73's in the axle, and still hill start in San Francisco. Then your top gear in 5th would be equal to running a set of 2.26's or higher depending if the 5 th gear is 0.79:1 or not.

RickWrench has used the S10 T5 gearbox on his old Round Body Falcon, and it, um, shoots up San Francisco's steepest streets with a 200.

:unsure: Perhaps shootin up wasn't the right word, butcha know what I mean....
 
Turbo charging is another way to squeak out more power and economy. I believe xctasy knows of some guys who turboed a 78 Fairmont 200 and got like 30mpg.

Imagine what the 144 mpg wise would get if that was a 200...... im thinking maybe 40 mpg man. Try it, let us know
 
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