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Discussion Starter · #1 ·
So, in a nutshell, though some dealing, I got a truck back I traded off in 2017, a 1984 Dodge D150 "Prospector". It smokes, but it runs good. I'm thinking of finding a good running donor engine and doing a swap (I have access to a junkyard) for something a bit better than what I have.My truck currently has the factory 318 2bbl with a 727 trans and 4.11 gears

So, I'm fairly certain I can find a complete running, pan to carb, flywheel to fan 318 for about $500... That I'd have to pull myself...

So my question is this, would I have any problems swapping an older 318, say late 70s truck or car motor apart from maybe the oil pan if it's a car motor? Will my accessories, water pump, alternator, and steering pump bolt on? Because, they're all new, and I'd hate to replace new stuff again. I know Chevy moved around their accessory pattern sometimes, and Ford changed a few things on their small blocks as well. I'm a bit in the dark on Mopar though.

Thanks for any help you can give, I'll be sure to document this uh, journey into saving a truck probably not worth saving. :D

84d150returnsthumb.jpg
 

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Should work just fine, there arent any real changes until the magnum era of smallblocks showed up.
- but you will look for a 360 arent you?
 

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The only problem with getting another used engine is the possibility of the same issue with smoking. More than likely, if the engine has good oil pressure, smoking is from the valve stem seals. What with all the new items on the engine, and since you are pulling her apart anyway, I would yank the heads, verify the valves are the proper colors (light black for intakes and white/grey for the exhaust), and change out the valve stem seals and replace the head gaskets. Takes a little more time than a flat out engine swap complete, but money saved and numbers matching is always a good thing. Otherwise, everything will bolt up between the old and new engine.
 

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That's a cool truck I will definitely be following this thread.
 

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I saw the mention of 4:11's and it got me thinking!!!

Thanks
Randy
 

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The hood ornament alone makes it worth saving.

I like that body style, and when I owned an '84 D100, I liked nearly everything about it except Holley carb and the gas mileage. The original side mirrors were smaller than what I liked, and one had a crack, so I bought a larger pair at a swap meet. It also had a 318 2-bbl, not the strongest engine, but a good workhorse. When I sold it, the buyer said he intended to put a 440 in it.

I second what Dana said about repairing the current engine. If you instead find a good deal on a completely running engine, why swap anything with it? Yes, keep the newer parts, but I'd only swap them as needed.
 

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Your post reminds me I still have the hood ornament off the 1990 I sold!!

They were high theft items for a while so I decided to remove it for safekeeping.

Mine was dark blue, EFI 318, auto, reg cab, long box, fine truck, just the right size.

Thanks
Randy


The hood ornament alone makes it worth saving.
I like that body style,
 

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I read elsewhere in these forums that federal law requires that when a vehicle owner swaps an engine, it must be from that model year or newer. I personally don't care; a late 1970's engine should be equivalent to your model year. Just be aware if your state has stringent inspection requirements.

If you go that route, one more thing to be aware of is that the lean-burn system was applied to the 318 starting with, I think, the 1978 model year. From the '73 to '77 MY, the ignition module is different. Maybe the distributor, too.

Your post reminds me I still have the hood ornament off the 1990 I sold!!

They were high theft items for a while so I decided to remove it for safekeeping.

Mine was dark blue, EFI 318, auto, reg cab, long box, fine truck, just the right size.
I also heard that they were often stolen, so I removed it whenever I drove the truck to Michigan. I never had a problem in Texas, though I don't recall ever seeing one available in a junkyard. I think yours was the last model year for the hood ornament, as the grille design was changed for '91.

Yours also had throttle body injection; not sure when that started for the 318, maybe 1989. Multi-port started for the '92 model year.

Mine had the standard cab, along with the standard bed, which made it maneuverable when parking. I think the '84 model year was the first for clear-coat; mine was peeling on the hood and fenders, and the roof was down to primer. It was brown, with two lighter shades of trim. I seemed to be the only one who liked the color; I could always find it in a parking lot.
 

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Assuming the truck engine followed the car engine timeline for the 2 bbl engines:
1984 was a lower compression, flat tappet, Carter BBD topped engine.
1985 had a compression boost, roller cam, high-swirl heads and a Holly carb. In the cars, these were tuned for higher octane but could run on regular with a knock sensor being part of the package.
 

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Discussion Starter · #12 ·
Thanks for the input guys, been working crazy hours this week. My truck is strange, the differential tag seems to indicate 4.11s, but the hood sticker says 2.94s. I know what 2.94s feel like, my Dad's 83 has 2.94s, mine certainly does not. It will also skitter both rear tires on pavement, so maybe some kind of Posi? It has the factory engine so far as I know, sans the smog pump, and a Holley 2280. And yeah, I'm fairly certain it is the valve seals because if I stand on the accelerator and make all 150 odd ponies or so these things came with work, it doesn't smoke. Smokes at idle a littleand at start a bit more depending on how long she sat.

Side note, I'm creating a thread to document what I've done to the truck.
 

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To do a quick rear end ratio check (fairly accurate), jack the rear wheels off the ground, put a mark on the tire (as reference, or a raised letter on the tire as a reference), turn the driveline by hand and count the revolutions the driveline has to be turned in order for that mark reference on the tire to do one full revolution. 4.11s will take four turns, 2.94s will take 3 turns, and 3.55s will take three and a half turns.
 

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On a vehicle of that age, I would not be surprised if the engine, transmission, rear end, or any combination of those had been replaced.

Posi is a Chevy term. Dodge usually called it Sure Grip.
 

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Several years ago I swapped a 318 out of a 77 Monaco into an 85 Ram 1500. The oil pan and the exhaust manifolds had to be swapped because of the configuration of them. Most everything else was a straight swap. I can't remember all of the details as a result of two brain surgeries in 2004. The guy I did the swap for was happy with the results, though, so I got my money!
 

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On a vehicle of that age, I would not be surprised if the engine, transmission, rear end, or any combination of those had been replaced.

Posi is a Chevy term. Dodge usually called it Sure Grip.
Addendum: The Chrysler design is the non-rebuildable cone style SureGrip; the Dana design also used by Chrysler Co. is the TrakLok (yes, same name as Ford's, which was also, shockingly, a Dana design ... )

I've got a TrakLok lined up to go into my truck, a 1988 Dakota.

RwP
 
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