Fuel Efficient Build---352 or 351W

[frnkeore]

I remember the Mobile Economy Run, very well, in the '60's. Huge amount of TV ads where sold for it. 

My folks bought a '61 Falcon Futura at the beginning of '61, with a 144 ci, 3 speed. A nice little car that got a actual, 30/31 mpg, with a 3.10 rear in it, about 26+ in town (if I wasn't driving it).

I know Ford was using high geared rears, by '58. My second car after HS was a '58 Edsel, 410 MEL (read 4500 lb, big box). It had a 2.89 gear and on the fwy, it could get, a measured 16 mph. I think that's when Ford changes it's thinking on rpm, as the 312 Ford-o- matic, had a 3.56, std ratio. Crown Vic's are now running final drives of less than 2.00 and over 40 mph per 1000 rpm.



I think their next gas saving strategy was weight, in the late '70's? when you started seeing lots aluminum, like engine brackets and air cleaners.

I'd still go with the 300, 4 spd OD or AOD and a turbo. Most bang for your buck.
 

[410bruce]

Well, after doing some online research, it seems no matter if the engine is a 300 or a 460 and everything in between, including the later model modular engines, the fuel mileage is going to be between 10 and 16 MPG.
Of course, there are cases where some, with modifications, get better or worse but for the most part, 10 to 16 seems to be it. My current set-up with the 300 being near the top, even with the C6.
So, the only "rational" reason I would have for swapping to a V8 would be for the sound, and of course the power increase associated with it.
For now, I'm going to give the ol' 300 a complete tune-up and a transmission filter and fluid change.
Will do a before and after MPG check and see if any gains were made.

[CV355]

Are you opposed to a Coyote-swap?    I average about 24mpg (60/40 city driving) in my '18 GT, and can squeak out 32mpg on the highway.

[410bruce]

Are you opposed to a Coyote-swap?    I average about 24mpg (60/40 city driving) in my '18 GT, and can squeak out 32mpg on the highway.

I certainly wouldn't be opposed to a Coyote swap, if someone would like to donate it to me. 

[CV355]

Are you opposed to a Coyote-swap?    I average about 24mpg (60/40 city driving) in my '18 GT, and can squeak out 32mpg on the highway.

I certainly wouldn't be opposed to a Coyote swap, if someone would like to donate it to me. 

I see donors for sale quite often.  They're not a dime a dozen like LS's, but they're a solid choice for a lot of builds.  Before our '69 Mach 1 project burned me out, I had hoped to do a 1955 F100 restomod with a Coyote engine. 

I ran mod motors for years.  Spent a lot of money making mod motors fast.  Then, I got this Coyote car and it was a game changer.  I have friends running Gen 2 Coyotes, bone stock engine plus blower/turbo, and they're squeaking out 800-1000hp with nothing more than fuel system upgrades as supporting mods.  It used to be that the same amount of money would get you ~400hp on a mod motor on a good day. 

[410bruce]

Well, a 1995 Mercury Marquis popped up my local Craigslist for free. 4.6 and whatever OD auto was behind them that year.
Car was left behind by a former tenant. Evidently was having overheating issues. It does have a title and is signed off by the owner. It's only about 8 minutes from me.
I'm thinking this may make a pretty decent swap. Thinking I may gain a mile or two per gallon, certainly no worse than I have now, I would imagine.

EDIT: It's already gone.
 

[Falcon67]

Gone - dang, that would have been a worthwhile catch I think.  Mod motors are interesting beasts from what I've read.  I still think a Coyote/blower swap into the dragster would have been a fun deal if the budget could have stood it.

[Temp]

Semi trucks went through  this along time ago.
It was found  the lower numbered rearend gears were better  for milage  and engine life than overdrive transmissions.
Class 8 semi trucks started  using  overdrive   auxiliary  transmission  way before  my time. Probably  the 1950's, than started using overdrive  main box transmissions. Like 
RTO-9513,  13 speed overdrive  in the late 60's early  70's.
It takes more power to turn the overdrive gears with  a higher  number  rearend  gear than it does to drive a straight  though direct drive trans with a lower rearend  gear.
Before it was figured  out there were 13, and 15 speed double overdrive transmissions.
When I was in high school  my dad and I built a car out of junk parts.
A 352 , 2 barrel  4 speed out of a 1967 ford f250 truck.
The chassis  was a 1979 LTD station wagon  cut down and shortened up.
The wagon  had a 2.26 to 1 gear ratio rearend.  We used the granny gear 4 speed out of the truck.
It would go 35 MPH in low first gear.
It would get 23 miles to the gallon on the highway.

[machoneman]

Yes, all those 'extra' gears do sap hp even before it hits the rear end gears. Direct drive after the transmission, so to speak, eliminates hp loss through an overdrive unit.

Heck, some here know this but those killer SS Hemi drag cars started using Chevy 12-bolt rear ends (or at least the center section) once someone pretty smart realized that the Ford 9" rear (or Dana 60 for that matter) consumed more hp than the hypoid angle of the GM based rear gears. Not much gain I understood but hey, max effort cars did go faster. Lesson is that the less 'drag' as I'll term it in the driveline = quicker e.t.'s or better fuel mileage.

[frnkeore]

I had actually considered just what you did, using the all syncro T19, in the 54 Ford car I'm doing.

I looked for and found a trans, drove 80 miles to get it but, when actually putting my hands on it, it was bigger and heavier than I had imagined and I would also have to use a cast iron bell. So, thinking it over and not knowing the 1 - 2 shift quality (have driven the T18 long shift) , I decided to pass on it.

I suppose running at a steady rpm, the gears wouldn't eat hp but, I can't imagine not eating hp in accelleration.

Here how it would be in a car, with 5500 max rpm. Not bad rpm splits, not like you would think a "granny" low gear would produce!!

[blykins]

FE in a full size truck and good gas mileage. That's a good one! Keep 'em coming!

351W is a pig too.

I had an '82 F100 Stepside with a 300-6 and an overdrive stick transmission. Down hill with a good back wind it might have gotten 15mpg. The power was nothing to shout about although those "in the know" touted the torque of the truck six. I am convinced a 302 V8 would do everything better.

Thinking a 4000lb brick can do better than 15mpg is a bit "optimistic". Those that say they've done better than that are putting their credibility on the line.

Case in point. I have a Jeep Wrangler with an automatic, 4.0-6, and 3.50 gears with 33" tall tires. On flat ground on the highway we may get 15-16mpg. Another example of moving a nearly 4000lb brick with a six cylinder motor.

My 2018 RAM 1500 with the V6 will routinely get 24 mpg with interstate driving.  On a "normal" week with running errands, stop light driving, etc., it will get 21-22.  It's a hefty girl at about 5300 lbs.

[babybolt]

My buddy had a 92 F-150 with the injected 300, 5 speed manual, supercab with a cap.  He would get 19 mpg and sometimes up to 21 mpg on longer trips.  The truck would still acceptably tow a open trailer with a car on mostly flat terrain.  The F-150 had the smaller trans, not the ZF installed in the 250 and 350's.

Tires do make a difference, the smoother summer tires are worth 1/2 to 1 mpg over mud & snow tires.

Easiest aero mod to a truck is a tonneau cover.

[JC-427Stroker]

Well, after doing some online research, it seems no matter if the engine is a 300 or a 460 and everything in between, including the later model modular engines, the fuel mileage is going to be between 10 and 16 MPG.
Of course, there are cases where some, with modifications, get better or worse but for the most part, 10 to 16 seems to be it. My current set-up with the 300 being near the top, even with the C6.
So, the only "rational" reason I would have for swapping to a V8 would be for the sound, and of course the power increase associated with it.
For now, I'm going to give the ol' 300 a complete tune-up and a transmission filter and fluid change.
Will do a before and after MPG check and see if any gains were made.

Some interesting reading on this topic. Thanks for putting up the question.

You stated that you don't tow.  Are you concerned about the build being able to tow well if need be ?

The fuel and timing map to go with the EFI will be very important.   I'd ditch the C6 for either a more efficient automatic or a 5 speed manual.    Tires and gearing are a Huge consideration for your mpg. The comments  regarding final drive gearing vs OD is something to consider. Tire type and dia go with the gearing.

I know the budget is always a consideration, but if you could find a Windsor stroker kit to build a 408 or an old crate motor 393" (4.03 x 3.85) might serve you well. If that's not in the budget,  the 351 with a set of World Products cast iron heads worked over a bit could pay dividends.

You probably have several more choices in modern dual plane intake manifolds with the Windsor than you have with the 352.  That's something to consider in your equation.  Get the correct camshaft for the engine, a set of Tri-Y headers, tire choice, driveline lubrication etc  and build a high mpg combo. Maybe you could get your OD Top Loader to match up with the right planning and math.

You could always look to build an efficient  high compression propane fueled engine ?  ...Now that would be a hoot.  Propane is about 104 octane.  I've not done one, but I've thought of it more than once. 

[410bruce]

Thanks for the continued input, guys.

Checked the MPG and according to my math, I'm getting 17, no highway use during this time, just in town and secondary roads.
However, my speedometer is 4-5 MPH optimistic which I believe would affect the odometer as well, so the 17 number may be incorrect. Probably lower.

You know, it's not so much about how much I spend on gas as it is at how often I have to stop to refill. I'm beginning to think this truck has a tiny tank.
If I get down to like an 1/8 of a tank or less (according to my gauge which is highly suspect), it seems like it only takes like 6-8 gallons to fill it.

Is it possible this thing only has a 10- or 12-gallon tank?

[JC-427Stroker]

Thanks for the continued input, guys.

Checked the MPG and according to my math, I'm getting 17, no highway use during this time, just in town and secondary roads.
However, my speedometer is 4-5 MPH optimistic which I believe would affect the odometer as well, so the 17 number may be incorrect. Probably lower.

Yes, yes it will.