Is there a conversion kit to install slant six in 1974 d100. Got to replace gas hog 318

Or maybe bolt on some late model junkyard 318 (5.9) fuel injection hardware and get better mileage and healthy dose more power than the Slant could provide for the same money.

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"Former Owner" of '65 Barracuda, 225, Auto, MP 2bbl intake, MP cam, Dutra Duals. Presently Moparless.

318 = 5.2
360 = 5.9

1992 was the first year for the Magnum engines (3.9 V6, 5.2 and 5.9 V8) with real (port) fuel injection. Pre-1992 engines can be "Magnumised", but it is not a simple bolt-on parts swap. Internal components need to be changed to provide oil to the top end. If the idea is to go to a later engine management system, it'd be simpler and probably wind up less costly to swap in a '92 or later 5.2 or, as much as I hate to suggest it, a 3.9 V6. But to answer the original question: No, there's no kit, but none is required, really. What you need is the engine mounts, the slant-6 engine and matching transmission, and some incidentals like throttle cable (and kickdown linkage if it's an automatic).

full-size trucks get lousy mileage pretty much no matter what you do with 'em, so do the math on such a conversion carefully to make sure you'll actually save money.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

3.9 v6 = BAD

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Yeah....Im the one who destroyed this rare, vintage automobile.....

Right you are and thanks for the assist Dan. So what about it? If mileage is the concern shouldn't he really just buy a more modern truck and count himself as money ahead over trying to convert and old one? What can he really expect mileage wise in a full sized PU with either a V8 upgrade to a FI version or a Slant swap? 16-18 mpg? 20? Anybody out there done that and had good results or is it time to for the OP to go modern?

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"Former Owner" of '65 Barracuda, 225, Auto, MP 2bbl intake, MP cam, Dutra Duals. Presently Moparless.

If mileage is the issue I'd buy a used Dakota.

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Official Cookie and Mater Tormentor.

But not a 4X4

A 2WD Dakota with a 5.2 and 5 speed will get 17-18 mpg overall and mid 20s on the highway. 4x4 will drop that 2-3 mpg and automatic tranny, AC, large wheels and tires, all will subract even more. My 98 fully loaded 4x4 gets about 13 mpg in urban driving and 18 or so on the highway. Another thing to watch for on a Dakota plenum plate leakage. On the 3.9/5.2/5.9 Magnum engines there is a steel plate covering a large opening in the bottom of the intake manifold. The gasket sealing the plate was prone to develop leaks. When it started leaking the motor starts to ping. The early factory "fix" was to pull timing which left the original problem unsolved. It stopped the pinging but destroyed the bottom end torque. It came to be known as the "Flash of Death." If I were to buy a vehicle with one of those engines the first thing I would do is replace the steel plate with an aluminum plate, available from Hughes Engines. You might also need to have the PCM reflashed to restore the timing. You can check for a blown plenum seal by removing the air hat and looking through the throttle body with the throttle plates opn. The floor of the manifold should clean. If you see oil residue then it's likely to have been leaking.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

This sounds very wrong, but in my 71 Maxi-Van when the 318 got tired, I put a 360 out of a wrecked Aspen R/T in it's place.
Did it for the extra power, I use this truck for trailer towing. But got a couple miles to the gallon in the deal.
Big vehicle smaller motor, does not allways mean better mileage.
For your pick up a 360 in good condition might be the best cheep option.
If you do. Get a torque converter fro the 360, or have the weights added to your 318 converter. Also the 318 and 360 have different oil pans, you would need a pick up/ van 360 oil pan.
I know there's a lot of reasons for other swaps, and they have some merit, but this is what worked for me.

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66 Valiant, 225.
84 Van, 225.
71 Maxi-Van, 318
60 Valiant wagon, 225
87 Maxi-Van, 318 4spd

depending on how the truck gets used you might get worse MPG with a slant 6. While it would be rock solid dependable, and this is a site geared towards the slant 6, if you haul or tow much with this truck, you might be better to do a GOOD and COMPLETE tune up on that smallblock, including checking compression (to rule out plain old tiredness) and your timing advance both mechanical and vacuum. You might just find out why its so thirsty. I would like to know why someone earlier said 3.9= bad. not a V6 fan in particular, but for a V6 it really is a pretty good motor. Ive had many Dodge trucks over the years (ONLY kind of truck to have ) from slants to smallblocks and even a 3.9 Dakota and Ive had very economical 318s (some thirsty ones too) and a few slant 6s on both ends of that measurement too.

...and camshaft timing.
Lots of vibration and noise, not a smooth engine, not a very economical engine, not especially powerful, not particularly long-lived. Just pretty mediocre all around. In its later iterations it's not especially bad, but in no case is it especially good.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.