StreetSleeper
Active Member
Also, engine manufactures sell 3.9 short or long blocks usually cheaper than the sum of machine work and parts for some engines
3.9 Stroker
- Thread starter 67autocross
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67autocross
A new iron curtain drawn across the 49th parallel
I have no problem with getting machine work done…my wife’s business shares a building with a machine shop… I stop in to visit everyday on the way home…she gets mad when I go into the machine shop before I go see her…
sccachallenger
Well-Known Member
If the crank needs turning anyway, wonder how much you could gain with offset grinding the rod journals.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Well, my 367/4-speed with a GVod is screaming for that truck body. You got a second one for me?
Dave_J
Well-Known Member
With the split rod journals I do not think anyone is willing to do a stroker as it would offset the splits even more. I'm not sure I'd even do an offset grind.
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67autocross
A new iron curtain drawn across the 49th parallel
You have to hide trucks like these around here….yeah that would be a perfect power train… slip on a 205 transfer case between the 4 speed and the GV
I had a 5-speed '88 Sport 4x4 when my wife and I started dating. Loved that truck and the 3.9 moved it along pretty good with the 5-speed. Looked at that M1 intake but never got around to doing it. Truck got hit and totaled in our driveway a couple months before we got married. Ordered a '96 V8 to be it's spiritual successor and still have it.
If I still had that 3.9 truck I'd probably look at a TorqStorm supercharger to wake it up.
If I still had that 3.9 truck I'd probably look at a TorqStorm supercharger to wake it up.
Hellrats
Just another dumbass
Just go to pull-a-part and get another engine. There are lots of 3.9 v6 engines in there. I was just at one here and that was the only engines in Dodge trucks. If it came with a 5.2 or 5.9 the engine was gone and the wiring harness was picked through. That should tell you something. If you were closer I'd give a 3.9. I have two to scrap right now. No one wants them.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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You ready to trade that heirloom yet?
You can keep the stereo, and the powertrain, just leave me a roller, lol.
I'm only about an hr and a half away.
Just my two cents, but if you are hell bent on keeping the 3.9 then I would put some KB pistons to get some compression, have a good valve job and bowl cleanup done, and regrind the cam.
BigStrok3
Mopar!
Too bad your not close to st louis mo I have a 3.9 that's about to head to scrap also. Pulled it out of my dakota convertible.
Hellrats
Just another dumbass
$1,250.00 for a kit? I just had a 5.9 shipped to my house with the wiring harness and PCM. The wife helped me put it in my 1997 Dakota last weekend. All I did was reseal the intake that always leaks. Runs great. Throw that 3.9 in the bottom of the lake where it belongs. Why they ever took a great engine and chopped off two cylinders I will never understand. And yes I said 5.9 in a 1997. You can use the 5.2 PCM with a 5.9, the PCM software has +/- 33 adaptive strategy and will adjust the fuel mixture just fine.
How about. A Torqstorm supercharger?
Dave_J
Well-Known Member
Spend $$$$ and get a 292 CI V6. With a lot of porting and big cam and get what, 350 Horsepower. I doubt anyone will get 350 HP without spending enough money to buy a nice 5 year old used car. More dollars than sense.
Where a 3.9 fits, most times a 5.9 will too and dead stock is near 300 HP and much more torque.
You all need to look at a 3.9's cylinder heads ports. Buy a few carbide bits and spend a week on them.
Two of the exhaust ports can clean up nice but the single is so Ba$tered up. So port the worst one first and set it as the benchmark to STOP on the other two.
Where a 3.9 fits, most times a 5.9 will too and dead stock is near 300 HP and much more torque.
You all need to look at a 3.9's cylinder heads ports. Buy a few carbide bits and spend a week on them.
Two of the exhaust ports can clean up nice but the single is so Ba$tered up. So port the worst one first and set it as the benchmark to STOP on the other two.
The displacement that matters is the air/fuel you can displace every minute (cfm) say 300 hp is about 470 cfm a 360 will need about 4500 rpm, 318 about 5100 rpm, 292 about 5550 rpm, 238 about 6800 rpm depending on efficiencies.
1969reddart
or is it Copper...
I bought a '93 brand new with the 3.9 - 5-speed.
That was a fun little truck. Wish I still had it...
Good luck with your Dakota
That was a fun little truck. Wish I still had it...
Good luck with your Dakota
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. The 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-up when 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...
Dave_J
Well-Known Member
The only way to do an acceptable stroker crank would be to ax the split rod pin and go to a common rod journal. This would require a bit of balance and it may shake anyway. Ligfhtest rods and pistons will help but inherent unbalance of a 90 degree V6 is hard to over come hence the split pin of the stock crank.
If you have a good block with low core shift you may get a 0.60" over bore or just sleeve all 6 cylinders and get a HUGE over bore. So the 292 limit is not really true.
And why stop at a 4 inch crank stroke? A 0.040" over bore and a 4.180" stroke to the 3.9 block will get you a 307 CI V6. Keep the compression low enough to put a Supercharger/Turbo on it and now you are talking major torque and HP.
(Dreaming here) This was a 100% truck engine so if Ma Mopar had pulled it head out its backside and did a 3/4 340 you'd have a 255 Ci V6 or used the 3.58 stroke crank have close to 275 CI V6.
Then do a 0.030" over bore and put a 4.180" stroke in for a 326 CI V6. Bit why stop dreaming and just do a 3/4 440....... 330 CI.
If you have a good block with low core shift you may get a 0.60" over bore or just sleeve all 6 cylinders and get a HUGE over bore. So the 292 limit is not really true.
And why stop at a 4 inch crank stroke? A 0.040" over bore and a 4.180" stroke to the 3.9 block will get you a 307 CI V6. Keep the compression low enough to put a Supercharger/Turbo on it and now you are talking major torque and HP.
(Dreaming here) This was a 100% truck engine so if Ma Mopar had pulled it head out its backside and did a 3/4 340 you'd have a 255 Ci V6 or used the 3.58 stroke crank have close to 275 CI V6.
Then do a 0.030" over bore and put a 4.180" stroke in for a 326 CI V6. Bit why stop dreaming and just do a 3/4 440....... 330 CI.
Dave_J
Well-Known Member
If I was playing the V6 game I'd do a 0.030" over with a forged 4.180" stroke crank, leave the compression down at 9:1 and push 5 to 7 PSI boost. Off boost would be a good unloaded power but on full boost around 365 HP and tons of torque.
Hellrats
Just another dumbass
What are you talking about? I have done V8 swaps in a 1993, a 1995 and the latest is a 1997. I put a 5.9 in the 1997 and it running on a 5.2 PCM. Hell I even used the V6 wiring harness on it just added the wiring for the #7 and #8 injectors. Same V6 transmission, convertor, even the motor mounts are the same. It's the easiest engine swap ever.
HELLO....ANYBODY THERE...??? 1989, NON-MAGNUM, THE SHELBY HAD A MODIFIED NOSE & ELECTRIC FAN TO GET IT DONE. THE ORIGINAL '87-'90 SQUARE-NOSE DAKS DO NOT JUST TAKE A V-8.
That's a 2bbl Carb V-6, '87 3.9, '88-'91's used 2bbl TBI units. Unless You go Magnum, which is shorter, & swap/adapt the whole harness & fuel system You go the Shelby-Dak route.
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