3.9 Stroker

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The body type in post#45 is the 1st designed to have a factory V-8, composite headlamp capsules & the nose is proud of the front fenders by some inches.
 
Bring over that 1989 and I'll show you a magnum swap would not be that hard. Using an electric fan and the newer magnum wiring would be a piece of cake!
 
There is not much wiring and a lot less fuel system BS is a magnum setup. Plus you can still get those parts. On top of that you wouldn't have to be worry to much on what PCM to use. No BCM to work around so the guages will still work. Hell you could use a ODB 1 system with one O2 and flash off the unwanted software in the PCM depending on what year you do with.
 
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But yea you may be right, it's too much work for some people. Plus it's gonna cost you. But it can be done.
 
Killer6 said:
Unless it's a Shelby Dak, V-8's are not a drop-in at all until they switched to the body like the red one above, that's why they changed the nose. T he stroker crank is probably more than it's worth just to get some more torque, but it would work, if it even needs a crank. I have a '90 TBI 3.9 that was locked-upwhen I got it for parts, soaked the cyls. with nano-penetrant for a week, then put compressed air in the cyls. & I got it to move. Now I can turn it over with a ratchet. I've seen those systems start dumping fuel all of a sudden, wonder if they're washing off the oil, then rusting up if left sitting too long...
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A la v8 fits fine. I swapped two 87s. one with a 904 and one with a factory 5 speed the one with the 904 took a friday night and all day saturday and it ran and drove. That includes pulling the engines and trannys from both vehicles the dakota and the donor diplomat. I had a drive shaft in my pile of driveshafts that fit fine. Used diplomat throttle cable and kickdown linkage. I cant remember what exhaust manifolds I used. probably D/W truck or the diplomat manifolds. Short spacer and a mechanical fan cleared the factory rad.

One of the easiest swaps I have ever done.
 
The main problem with 6 cylinders is you got 6 intake and exhaust ports, 75% of the power capability of a similar V8 head plus smaller displace gonna need more rpm to make power. A 375 hp 6 cyl is a similar build to a 500 hp 318/390. 300-400 hp is a decent range for a 318, which is 225-300 hp for a 3.9l. Not saying don't build it but don't expect much from it. Unless turbo is a possibility.
 
My '88 (flatnose) Dak with a 5.9 using a Durango pan and sitting on V6 mounts. It's got an LA front on it (timing cover, aluminum water pump, pulleys and alt. brackets). I did have to move the radiator forward a bit ('62 Corvette), only minor sheetmetal trimming and the rad fit like it grew there. An aftermarket radiator was considered, but the Vette unit won out because I already had it.
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Mechanical fan, no spacer. I could have saved another inch by using the early iron water pump, but this whole thing was a matter of using what I had. The Magnum pump would have only saved another 1/2" over the iron pump, but I wanted to declutter and get rid of the serpentine system. I also wanted to run a mechanical fuel pump, since the truck was originally a carbureted 4 banger and didn't have the in-tank fuel pump.
Shelbys used the TBI LA engine, but moved the engine back almost 2 inches with custom mounts to get the necessary radiator clearance, and then used a modified B van transmission crossmember. I didn't want to bother with that, since it would have meant relocating the 5 speed shifter hole back and getting a new, shorter driveshaft. Remember, I wanted to do this on the cheap with parts I had laying around.
So I ended up with a 5.9 Magnum, 5 speed 2wd short bed Dak that da** near bolted together with all factory parts (okay, the rad is a GM factory part, but still...) the way Shelby "shoulda" done it.
The only concession I made to Shelby was using GLHS buckets to replace the busted up bench seat...
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So, if you're looking to do this with a 4wd Dak, this is how you want to do it, not how Shelby did it- if you move the engine back, then you have to fab your own engine mounts, deal with transmission and transfer case linkages and crossmembers, getting two different driveshafts, and probably messing with your pinion angles on the front and rear diffs.
 
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Hellrats said:
There is not much wiring and a lot less fuel system BS is a magnum setup. Plus you can still get those parts. On top of that you wouldn't have to be worry to much on what PCM to use. No BCM to work around so the guages will still work. Hell you could use a ODB 1 system with one O2 and flash off the unwanted software in the PCM depending on what year you do with.
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'87 15 & 20gal fuel tanks were 1 year only and had a non-pump sender/pickup as well.
'88-'90 had 15 & 22gal tanks, both different than the prior tanks, and had a TBI pump module.
'91-'96 had yet another 15 & 22gal set of tanks, '91 had a different TBI pump module than the prior tanks, and the '92-'96 tanks used the new Magnum system pump module.
There's a lot more to dropping a Magnum into a square-nose than fitting the engine in there.
 
You are right it can't be done. No one could ever make it work... ever.
 
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Some cars you could never fit a Mopar A engine into without a huge remake. This is why when Chrysler bought the Sunbeam car line of the Shelby TIGER, They had to sign a deal with FORD to supply the 260 and 289 Ford V8 as a 273 would not fit the small chassis. The 273 was too wide. But with a longer nose a \6 would have worked. ;)

In the 70's I owned a Tiger with a 260 2bbl 4 speed. DAMNSNAPPY car.
 
You can't put a Chevy engine in a Ford either. It won't fit.
 
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Hellrats said:
You are right it can't be done. No one could ever make it work... even.
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Hmmm, well, I don't recall saying or hinting anything "can't" be done.... it's one of the terms I Freakin' hate. OP stated He did not want to do it, and it is not a "drop-in", but You seem hell-bent on talking Him into it....for no real reason other than "that's what I'd do".
He asked about a stroker crank if the crank needs replacing, have a nice eve. Dude....
 
Well, I was just giving him an option. You took it to a new level. It will fit as other people have showed you in this post. It's up to the OP how he want's to go with it. If he finds a stroker kit good for him and I hope it works out. You are the one "hell bent" for some reason. I have done a flat nose "early" Dakota swap as well. It is a bit more work and the magnum fits better if you use the LA front end and an electric fan. The fuel tanks can be changed as well but I'm sure you already know all of this. Oh and... By the way thank you, I did have a nice evening... Dude :)
 
I'm just curious, & waiting to find out what caused it to lock-up, it's a shame there aren't more members closer with an "unwanted" replacement.
 
Killer6 said:
I'm just curious, & waiting to find out what caused it to lock-up, it's a shame there aren't more members closer with an "unwanted" replacement.
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Oddly the 3.9 never seemed to be as reliable as its v8 siblings. Around here a used replacement would be a little tough to find. You could always grab a reman from a parts store.
 
He did say it has been sitting for a while. To bad he is so far away, I have a running V6 just pulled but sitting behind the shop. But it is very tired. 226,000 miles and it has never been apart. My brother bought it new and it has always had the oil changed every 3500 miles. But it is really worn out. He can have it but shipping would be a killer.
 
HankRearden said:
Oddly the 3.9 never seemed to be as reliable as its v8 siblings. Around here a used replacement would be a little tough to find. You could always grab a reman from a parts store.
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I don't know, My '87 is at 170K, and if it weren't that Trusty Rusty got to the point I wouldn't sticker it again I'd drive it anywhere w/o a 2nd thought. Even with the 2bbl carb.
 
Not sure on the un reliable part. Hit or miss perhaps. My 03 dakota with it’s 3.9 just passed 401,000 this week. I bought it new 21 years ago. My daily driver
 
I think it locked up from snow blowing into the open element air cleaner…. It had been sitting for 5 years maybe 6…I will try to get it apart this winter and will post up some pictures of what is wrong with it…probably will even dyno it before it goes back in…
 
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