68Chero

I know it's a long post, but I'm trying to tie up some unsettled questions about EFI - All my questions are with "driving conservatively" in mind.

5.0 swaps are getting very popular these days. What kind of MPG you guys getting from swapping a stock 5.0 + AOD into your larger bodied Rancheros? I am looking to setup my 68 for commuting to work.

The web is full of conflicting data and I'm trying to decide if I want to go this route.

My 351C 2v (stock) with Pertronix + C4 combo can get 15.5 mpg driven 45-55mph highway. *I said highway, not freeway meaning I am going the speed limit* It can also get 11mpg if I'm horsing around in town.

What I know...(please correct me if wrong) Replacing a C4 with an AOD should increase economy by about 30% assuming the rear end is geared appropriately. That would mean that my 351C "as is" could get 20mpg.

In order to justify the $$ and effort, I am trying to set a goal and reach/exceed 25mpg freeway.

Things that I have considered so far:

-Roller cam/lifters into the 351C - might yield another 1-2 mpg
-Stock vintage 302 to replace 351C - Seems like no advantage as stock 302's seem to be underpowered.
-Late model 302 block converted to carb - still trying to figure out if worth it.
-Full 5.0 efi swap - looking for MPG data.
-EFI plug and play kit for 351C - Too darn expensive LOL
-Will a eddie performer manifold w/ 600cfm 4bbl get better mileage than a steel 2v 2bbl manifold and 2100 1.08 jet ? Someone told me it would due to better dispersion.

The questions that I'm left with are: what gain does EFI have on the same stock 5.0 engine vs. the carb. and what MPG can I expect from a stock 5.0 EFI engine if driven conservatively. I think the Ranchero weighs about 3300lbs. but I can't find the spec anywhere. Thanks again for any feedback.

In the end, I would prefer to keep the 351, because it's been a very reliable motor but MPG is the ultimate goal.

Mroldfart2U

I am unsure of the 'advatages' of the 302 swap for fuel milage gains. To me backing up in CID would be counter productive for the intended out come. (the 302 would have to 'work' harder than the 351). I would think the best bang for the buck would be an aod conversion and a rear gear swap. I am assuming you are geared at 3.00:1 right now. 15.5mpg isnt bad actually, but can probably be improved on. Maybe have to lower your goal down tho to the 20-23 mpg range. JMO of course....



MRO.....

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Cheap, Fast, Reliable... Pick 2...
'70 Mach1 351C 4v 4sp 4:56's Been abused sense '79, needing tlc
'61 Fairlane 500 292 2v Cruise-o-Matic also needing tlc

5.0 Chero

I did the swap over 10 years ago on a 73 Bigger and heaver than 68, I went from a 400 boat anchor to a 5.0 HO/AOD with 3:50 gears. With the 5.0 I get about 22 MPH cruising at 70 to 75 turning about 2700 rpm. The 400 got about 10!
The 5.0 is quicker, more fun to drive, easier to start, and more reliable. The PYL is and has been a daily driver (Primary) for about 13 years now. I am on my 3rd PNP junk yard 5.0 now cant beat a $150 motor that lasts 5 years or so.
I scored a 408 stroker Windsor from PNP last year and it will find its way into the PYL next.

210eddiep

What year 5.0HO/AOD and is there a lot wiring to do?

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Eddie

5.0 Chero

87 to 93 mustang Mass air wiring all depends on who's and what you use.

68Chero

Thanks for the feedback.

Are all 5.0's from that year range created equal or is mustang the silver lining? Same question on the AOD's. I am thinking about picking up a donor car and Thunderbird's , town cars etc. are alot cheaper and not all modded out.

PSIG

If using a full engine, wiring and transmission from a donor, then any year/model 5.0L will work. I strongly suggest 1988 AOD and newer for best reliability. Also note, the standard 5.0L (most T-Birds, Town Car, CV and Marquis, etc.) use the old 302 firing order, but may be used with either firing order. The HO 5.0L and 351W systems (Mustang, MkVII, some T-Bird, 5.8L E/F-trucks and vans, etc.) use the 351 firing order, and must remain that way for proper function for the sequential feature and O2 feedback scheme. Using a SEFI system with the wrong firing order confuses it, and swapping wires does not fix that issue.

Considering this, an HO or 351W system could be used to run a 351C with an adapted EFI manifold, but not suggested for a 289/302 due to firing order. The standard firing-order systems can be used for either firing order, making it more flexible. The primary up-side to the HO systems is increased stock MAF flow for modded engines that need it. That does not appear to be your need. If it becomes a need, the system can be upgraded with larger MAF and injectors to suit, with tweaking of the programming for best performance (including mileage).

Bottom-line is that all of the MAF 5.0L systems and cars can be donors, if a matching firing-order engine is used with teh HO version. Sequential EFI is primarily for emissions, and so it's not a primary factor in choice, though it can help a tiny bit with MPG. In-fact, a '62 Galaxie using a full 1990 Marquis driveline swap made 26 mpg at typical 60-65 mph speeds, measured over it's first 450 mile highway trip. Not bad I'd say.

David

[EDIT] Corrected firing-order statements to reflect universal capability of non-SEFI systems.

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OleDutchD

Agreed that EFI would likely be beneficial, but also agree that power-to-weight ratio plays a role.
My first intermediate was a '72 Ranchero w/ a 400/C-6, 2.75 gears and 28" tires in back (L60-15's). Swapped on an Edelbrock SP2P intake/600 VS and added headers and dual exhaust. Highway mileage was consistently in the 22MPG range (as long as you stayed out of the secondaries) and 16 or so around town. Point being that it's all in the combination. A larger motor will labor less to accomplish the same amount of work of a smaller engine in the same chassis.

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My427stang

I think you would be unlikely to make any significant goals with an engine swap. At least not enough to pay back the investment.

Your mileage is pretty good already, but if you wanted to play with an AOD, you might get a little better, but keep in mind you don't want OD to be too tall. A compound ratio (OD x axle) lower in numbers than about 2.75:1 may hurt you. So consider that you may need to make a gear change to stay there, also not cheap

Another thing you could do is blueprint the motor you have, to include advancing the cam, measuring static compression ratio, determining dynamic, adding headers, and basically optimizing your setup.

The combination of an AOD and a stock motor with a few improvements could get you a couple MPG city and maybe meet your goals on the highway

Unfortunately payback will also be slow, but you will have a lot of fun doing it because the car will run so much better.

Ultimately though, it'll take money, so if you are doing it for fun, awesome, but if you expect it to be profitable, its probably better to download "Gasbuddy" on your phone and find the cheapest fuel in your area LOL

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70 Sportsroof, 427 FE/489 cid, TKO-600, 31 spline 4.10, A/C. modified Mass-flo EFI/CnC ported Victor.

Butch Evans

68 chero,

I had a 64 Ranchero with a 91 fuely motor and An AQD that got 29.8 mpg on the Hwy. Also with a 3:25 gear. Wish to God , i still had it.

Butch Evans(Falconeer)
Thomasville NC

Callout

Why go to all that trouble? Have you considered a gear venders overdrive?
Like this for a C6:
Installing a Gear Vendors Overdrive to C6

68Chero

These are very cool indeed. A little on the pricey side..GV units are economy for the wealthy.


I'm not looking for massive gain....I'm younger with kids (plural) and wife. They are all very supportive of my attachment to this car...but I want to try to justify having it by making it commutable.

I do appreciate the posts - very good info. I think I'll get the aod in and a good set of gears. See what that does. If it's no bueno, maybe look at swapping out for the FI.

351C in a 68 is cool to begin with - if it made mpg in the 20's that might be hard to top.

chunger

Not sure if you've decided what to do yet, but thought I should chime in here since we're pretty much in the same boat.

My ranchero has a late model 302 with a carb. I'm running what was originally a SEFI 302 out of a Crown Vic. Got the entire motor in trade, ironically for a '73 Cleveland. I've run both the stock SEFI cam and now the 302 HO cam (roller). No appreciable difference in mileage, but better power and nicer sounding idle with the HO cam.

I should mention that 15 years ago, I had this exact same config in a '67 Fastback and got 17-18mpg on the fwy. With this setup in my Ranchero all I can get is 11 in town and 13-14 FWY. Yes, we're in CA, and the gas sucks, but still, this seems low to me.

I'm running a T5z with .62 o/d and the stock 3:00 rear end. It might benefit from lower gears. At 60 mph, it's turning 1500 rpm. Too low I think.

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-chunger
'68 Ranchero 500
'70 Cougar XR-7 Convertible
'98 Mustang GT Convertible

turbo2256b

I have built engines for economy and performance. A few even went to sefi to carb and carb to sefi. If everthing is matched up and tuned realy well (the comple engine build) there isnt much difference in economy. One engine ran a victor efi then went dual quads set up by Nickerson, so far the carbs have done better by 2 to 4 mpg.

PSIG

Time are changing fast. Not only is fuel getting more expensive, but the cosnistency is getting really bad from station to station or batch to batch. Consumer groups have reported some awful "cutting" of pump gasoline by adding higher than specified levels of ethanol. One station tested to 48% ethanol in a sample of their "10% ethanol added" regular-grade gas. They make substantially higher profits doing that.

The point is, a perfectly tuned carb setup and a perfectly tuned EFI setup will get roughly equivalent mileage. However, if you get more or less ethanol in the next fill-up, only the EFI will compensate for it without you even realizing it. Carbs simply can't do that. That's where mileage, power and driveability fall on their faces, and unless you are a tuner that carries parts and extra time around to re-tune it as necessary, you're at a severe disadvantage to EFI.

There are dozens of other advantages to EFI, its combined ignition control and other features that I won't include here. Carbs are cool, and I have run and tuned them for many years (and still do) but they are simply out-matched in almost every way by powerful modern electronics. My favorite example (though I have many) is still my 5500-pound work truck and small-block. I did my own home-brew EFI conversion and it saved $600 more than what it cost to convert it in the first year alone. Do what makes you happy. My 2 cents.

David

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