Truck/Van application. Most likely with a manual transmission. Diesel or Gas, NA or Turbo. Not while hauling a load, but during normal highway/city driving. It would be great to get some real world numbers from member's experience. I'm new to Ford, so please be easy with me I'm also poor so late model stuff like the ecoboost are out, but I'd like to know what they get in real world use and swapped into older Fords.

Here's a few engines I'm thinking of:

2.0 Pinto Turbo like used in the 80's Turbo T Bird & XR4Ti. Not sure how well this would work. I'm not looking to haul loads and I don't have hills to deal with.

Straight 6 any

V6 any

Diesel V8 IH IDI

Small Block Gas V8 any

 

What MY/class of truck or van?

2.3 would be the turbo 4 cylinder. May be under power/ torque for a heavier rig. More so since the turbo builds power/boost at higher RPMs and that's not where you'd want to be to try and produce good MPGs. Trans/drivetrain would be a little lite duty in a full size.

4.9 FI with 5 spd was a very good all around work horse, decent mileage, power and torque. Fairly easy to source.

V6 ?

6.9/7.3ID= heavy ( see weight class, generally needing 250 series or higher for weight/suspension) output power 'fair', expensive if needing build for swap.

Small block and man/auto plentiful, 302 easy to accommodate and or source from salvage yards etc, better if FI.

Back in the 70's we used to retro F series 250/350 with Perkins and Detroit diesels. Sizeable job, costs to convert over fuel mileage gains would take a very long time to see the payoff, if any.

We used to have and answer this question... How fast can you make it go, and whats the highest mileage!? The answer was always,, how much money do you have? 😉

Meaning, when making a choice the costs involved to covert ( over what you think you may see in increased mileage) has to be taken into consideration. Sometimes the cost of a swap can buy a lot of gasoline. There are 'always' costs involved that are unforeseen or expand during any transformation. Down time (garage/shop space during the conversion if that applies as well.

Electronic control is something else to consider, most later power plants/trans are subject to needing some direction to run. Carb, or old school Mills make for a much more simple swap, and did ok on their mileage, depending. But, generally FI Control are the preferred, but again, harness and components have to be part of the plan. If you can score a complete donor for engine, trans, harness, PCM and such, it tends to be cheaper then bit sourcing and the time lost to do so.

My .02

 

1980s most likely.

Van would be the full size Econoline probably a 3rd gen 1980s. I'd be fine with a 2nd or even a 1st gen if I could find one in decent shape. FL is a bad state to find old cars. With the 3rd gen Econoline, I thought the body is the same except the extended back some have, just the brakes and suspension are upgraded for the 250 (1/2 ton) and 350 (1 ton) models.

Truck would be a 7th or 8th gen F-150 maybe an extra cab 2 wheel drive or a 1st gen or 2nd gen Ranger.

2.3) I'm not worried about being slow and under-powered, if it saves me on fuel. What are the 2.3 Diesels like?

4.9) What numbers do those pull with a 5 speed? How about carb vs FI?

V6?) Cologne V-6

Not enough $. It will have to be a Craigslist or self service wrecking yard sourced swap. I am aware that it takes a lot of driving to turn a few MPG improvement into a net savings. I'm used to driving cars that get high 30s to mid 40s, so getting into the 20s would be great. I'd have a hard time driving something that's getting in the teens.

I'm fine with basic electronic ignition and fuel injection. I'd rather not touch anything OBD related, unless that stuff can be removed and replaced with older electronic controls. I'd be fine with aftermarket stuff like MegaSquirt, but I doubt that it would be cost effective compared to factory stuff.

 

The FI 4.9 5spd would get low 20's 'depending' on conditions,, meaning driver habits, loads, grades, altitudes, ambient temps and such. Actually all will be held to the same conditions. A manual trans driven wisely generally tends to get better MPG over an auto, but again, conditions.....

Its a matter of physics, weight, power/energy to get the weight or mass in motion, and keep it there. You can't overly 'skimp' on HP/torque or the MPG scale tends to fall off and so does mileage numbers.

To small and it works to hard, overly large and may suffer fuel MPGs. The balance would be to find a power plant and 'gearing' that compliment both or each other. Gearing if not correct (even with a good engine trans combo) for the type driving you plan on, or not matched to the engines output HP/torque can have negative affect on MPG even if your trying to use a fuel miser engine. If your doing a lot of long range driving, even a overdrive of Gear Vendor type spliter may be of a benefit.. But with an overdrive, you'd need the power and torque to pull through the higher gearing ranges.

A small displacement engine if your foot is always buried to the floor or held consistent with steep 'throttle angles' just to get up to speed works to hard to be fuel efficient.

The key may be to find a donor (wrecked etc) for the swap. That way most everything you need is readily available.

 

I could live with low 20s. Thanks for all the advice. The van I'm interested in has the 4.9 with a feedback carb. If I get it, I'll probably convert to later factory FI. It's got a stock 4 speed overdrive (4 forward speeds + reverse) manual transmission. Will the later 5 speed transmissions bolt up? Do I just swap bellhousings or do I need to find a 5 speed from a 4.9? Is there certain ones that are better then others? If the Mazda made ones fit, are they also used in any US Mazda SUVs? Is it easy to swap gears, especially 5th?

 

The M50D R2 was an integral/one piece bellhousing trans type, hydraulic clutch application. It'll bolt up to any 4.9 but the other components will need upgrading. Meaning clutch, hydraulic master, drive shaft etc.

4.2 and 4.6 would be a possibility with a M5 overdrive type box.
By gearing, I was referring to rear axle gears for the best match to what ever engine trans combo you go with.

Adding OE FI to a NA engine would be considerable work, and this is where a complete donor comes in handy as far as the newer engine harness, PCM and such. If you went with a 4.9 it may be easier to pickup the later model donor equipment and then sell off the old power plant and drive components.

Even something like a NA 302 with an add on overdrive is an option. 4.9 and 5.0 power numbers are pretty close with the I6 slightly higher in torque I believe. But a contender.

We used to replace a lot of F series 5.0's with Mustang etc 5.0 HO motors since they tended to be plentiful at the salvage yards, and priced fairly well over exchange engines or rebuilding.

E Series are fairly heavy, and doing what you can to reduce weight always benefits MPG. But no matter, I'd doubt you'd ever see much over high teens to low 20's pushing a reasonable heavy box in to the wind 😉