alright, this is maybe not the right subforum, mods- feel free to move it as neccessary!

now that *that's* been said- this'll be longish, so bear with me:

I have a 2003 F350 long wheelbase, crew cab, 8 ft bed, 2wd dually with the 6-speed trans and a 6.0 that's been paid for for years with ~160k on the clock.
The injectors are toast (again), and there may be other issues. I've pretty much had it with replacing parts that are just going to fail yet again, and my options are down to:

1- get rid of it (hate to, I love the truck other than the engine), or

2-swap out for a different engine. I know more than one guy has swapped out for a 12v Cummins, but I'm thinking going in a different direction: I'm thinking find an early 90's donor truck with a 4.9L inline 6 and a five speed, and swap out the engine and convert to gas. I'm of the opinion the 4.9 has ended up in F-350s right from the factory, and while it won't be a speed queen (not a concern, my 'go-fast' days are loooong behind me!), it should have the torque to do what I'll need.

My mental list has gotten as far as: I'll need to make/modify the engine mounts, I'll need to make an adapter plate to mate up the 4.9 with my dually's 6-speed, make/modify the exhaust (salvage what I can of the diesel's exhaust), and pull the engine bay wiring and computer from the donor truck. The dually is a base-model XL with the only component not full manual is the intermittent wipers (no power door locks, no power seats, no power windows, etc etc etc) so I shouldn't need the engine wiring or ECM for the 6.0.....

You guys see anything I'm not thinking of? Anyone know of someone doing this in the past? Anyone think I'm going premature-senile?

This is still in the 'idea' stage, weighing the pros and cons, and convincing SWMBO that this is a great idea!

I'm a fairly skilled guy, currently I'm the lead machinist at a mid-sized weld/fab shop and have been cutting chips off-n-on since high school (mid-80's), with a 4-year break to go see the world as an A-gang MM in Uncle's Big Gray Canoe Club, and a few years working in car and motorcycle shops so I'm not seeing this as being outside my skillset.

random thoughts and opinions also welcome!

 

sounds doable, if you know enough about electronics to be able to convert the older computer to work with your truck. or you could go with a carb and run all mechanical gauges.

 

Overall sounds very doable.

As long as the dimensions work out reasonably (length, width, height, oil pan to crossmember and steering components, all based on crankshaft to transmission alignment).

Not sure if either engine has a mechanical fan at the front, but if so, you can run an electric to pick up some clearance and not worry about alignment of the originals.

Mating to the 6-speed is where I would put in some more study. Not the physical aspects of an adapter plate, but the engineering of comparing gear ratios and steps between gears comparing the two engines' power bands. Are the gears going to match in steps and range? Are you going to bog or over-rev at typical speeds? You might find a different rear gear can help put the power band where you need it, as long as the steps between gears are sensible.

Accessories... Power steering pump? A/C? Will your radiator work with the replacement engine? I think that one is likely "yes" but do a little comparison.

I'm assuming the truck condition is past worrying about resale value. And assuming you have no smog issues to contend with.

As to SWMBO, just remember it is not about the nail. It is never about the nail.

 

offer she who must be obeyed a choice.
$1,000 for you to do the swap, or $80,000 for a new truck.

 

Does the truck have hydroboost brakes? You'll have to do something about that too, but swapping over a vacuum brake booster from a gasser won't be much of an issue.

If you had a gasser tranny, getting an adapter plate from a Ford Modular tranny bellhousing to a Ford small-block bolt pattern wouldn't be too hard to find. (Doesn't the 4.9L share the same bellhousing as a Ford small-block?)

 

WAG- without having the hard gearing numbers in front of me, I *suspect* it will work with the 6-speed that's in the dually, it has a creeper gear, 4 drive gears, and and overdrive, and *seems* similar to the various 5-speeds I've owned in the past, and all gears have a pretty broad overlap...I will definitely be investigating that more.

good point on the actual physical dimensions, will have the tape measure out next time I'm in the shop.

other things like power steering, AC, etc I'll take what's on the donor engine along with the engine.

resale value for the shape it's in (bad injectors) is pretty low, and replacing the injectors is looking like about a break-even considering the cost and my time putting them in when it comes down to 'actual dollars in my pocket' when all's said and done.

smog isn't an issue- diesels in Md weren't subject to emissions at the date of mfg, and it's registered as a diesel, soooooo.....

 

smart! Veeeeery smart!

 

What about emissions testing/inspection? Usually
DMVs don't like engines swapped in that are older than the vehicle. In VT trucks over 8500lb don't need to do emissions, at least for diesels, not sure of gas. You going to keep it registered as a diesel? Of course when you do want to get rid of it, you will probably have to sell it as parts as I doubt anyone would want to deal with it as a running vehicle, especially with a small in line 6. I think you should go 460, probably get about the same mpg but have a lot more power. Build a high compression low rpm engine.