V6 3 speed manual

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Mr Shine

Mr Shine

At 12 dad said “Tear this 318 apart”.I was hooked.
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Jan 23, 2008
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South Texas
So call me crazy....
My 65 Valaint 4 door currently has a Slant 6 -3 speed (tree).
I have a 3.9 V6 I’m going to put in it.
Before anyone says “Just put a 319-360 in it”....not gonna happen. I want the 3.9. It’s unusual and rare, so ...done deal.
Now for the good stuff.
I want to keep the 3 speed to make it even more unusual.
I’m pretty sure a V8 bell housing will work. My quandary is, anyone have any idea what flywheel-linkage parts-driveshaft combo I might use?
Thanks for any input beside”V8 it...your wasting your time”
 
The 3.9 will take a standard 318 bell housing. It is a 318 sans two cylinders and the same crank minus a rod throw to make it an odd fire configuration. A member here by OneBadColt had one in an early 70's dodge colt with all the MP goodies thrown at it. What year do you have? High swirl or Magnum? I personally like the 3.9. Headers are probably going to be a pain though. I like the 3.9 V6, although many others do not.
 
My 3.9 is out of a 91 Dakota, so the early 1st gen.
Was planning on keeping it stock, manifolds, intake, etc.
I’m guessing that I can use the flywheel from an early 318 on it.
Trying to figure out which fork I’ll need and if any of the linkage will need to be modified or if I’ll need other parts from a V8 car.
 
Stay with the hydraulic linkage that came in the Dakota. It makes life exponentially easier. It’s been a while, I can’t remember if the 3.9 is an internal balance, but it seems like it had extra material on one side of the flywheel on account of balance/firing order. I’ll have to double check for you. Manifolds will make your life simpler for sure. Are you just putting a big two barrel on the stock manifold?
 
Non- hypo small block V8's in light duty cars and pickups, and your Dakota V6 used a 130 tooth flywheel and a 10.5" clutch. Easiest to buy a complete, matched setup (bell housing with throw out arm and dust shields, and flywheel) from someone if possible. I agree with prior poster that the Gen 1 3.9 accepts all Non-hypo clutch V8 components like bell housing, flywheel (of proper balance type), clutch, etc. that a non-hypo V8 uses. If you find a V8 3 spd bellhousing you can use your transmission and driveshaft. If your upgrading to a later style/heavier duty type 3 spd used in most applications after 1965 you'll need a slip yoke type drive shaft to match the trans and have it shortened. While I agree with other poster that a hydraulic clutch is nicer it is a lot more fabrication and modification. Given the setup your car currently has I'd use a Borg and Beck style pressure plate/clutch assembly. If you switch to a hydraulic clutch I'd use a diaphram style clutch assembly.
 
I like the idea......but there's nothing "rare" about a 3.9. They made millions of um. Maybe the swap is rare, I guess that's what you meant. Keep us posted. It'll be cool and different. Less power than a 318 and no better mileage, but it'll be cool.
 
Someone on this site has done the 3.9 swap already, but the member's name escapes Me, nice job with retro dressed valve covers etc. Don't think they went manual trans on that one, check the interchange on the flywheels for the same years v8 to v6, if they're different they carry imbalance. If not they're neutral.
 
I caught an error on my previous post, thanks valiant patrol... I mentioned Dakota hydraulic set up but the one you would want would be full size ram with 10 or 10-1/2 inch clutch, bell housing and hydraulic slave cylinder used behind a 239. The Dakota’s I am familiar with had the bell housing cast as part of the transmission case. I don’t believe that bell housing will have a bolt pattern for a three speed either, but if it’s one of the iron ones for the NP 435 it should have enough material to be safely milled, drilled, and time-serted. But if it were me, I’d use a small block safety can, no such thing as overkill when it comes to clutch safety.
 
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I like the 239 well enough for that to be my “go to” if I were doing a six cylinder Mopar anything (well, unless it’s a diesel, then it needs to be either a Cummins 6BT or a good old archaic Detroit 6 series). I am in agreement with Rusty that it is a very cool and different build option. Basically a high swirl 31 with roller cam, 9 plus something to 1 compression, and more power (especially torque) than a slant. Stone ax anvil reliability too.
 
Thanks for all the replies. I don’t have a manual from the Dakota, it’s a 518 auto, thus the 3-tree from the Valaint.
Using a hyro from a newer truck is a possibility. I am leaning toward staying with the old school trans and linkage tho, it would keep the driveshaft issues fairly simple I think. Wondering if I need to change the throw fork to a V8? Or is there any difference on the early stuff?
 
Yes. The slant 6 clutch linkage assembly is much lighter duty than the v8 outfit. You will need a factory service manual for definite on this project. In your case and going with a factory bell, I would go with an early A bell housing (if it is available to fit the 130 tooth 10.5 inch flywheel) and change the linkage if need be to the V8 setup. It may possible to run a light 10 inch clutch and keep your present linkage if it will bolt to your present bell housing. Hopefully, some more members of the early A crowd will chime in on the bell housing size. I am wanting to say that they used a 10 inch clutch and I am uncertain of the flywheel comparability. The \6 used a 9 inch clutch, so the clutch linkage may not even like a 10 inch V8 setup.
 
The A903 3 speed is non-synchronized first gear unit with very small ancient-technology synchros that are light-duty,slow-shifting,with ratios to match the original engine.You know downshifting into first is gonna be a pita,right.If you spend all the time and money to install it, and then blow it up, what's your back-up plan? If you keep it, I recommend to buy a spare trans asap and a source for new brass rings.
If you just gotta have a 3 speed, I recommend the A230 with a floorshift. It is fully synchro'ed and shifts easier and faster, and the V6 will never break it. And the bonus is that it bolts right onto the 318/340 68 up bellhouse. You will need a new driveshaft.
But if I was going V6, I would bolt on an AX15 5 speed with ratios of; 3.83-2.33-1.44-1.00-.79od..This will work well with 2.76s to 3.23s
The A230 has either; close-ratio 2.55-1.49-1.00 or a wide-ratio of 3.08-1.70-1.00
As to the 903 ratios;I don't recall them; maybe around 2.95-1.54-1.00; I'm guessing.
 
If you were in the neighbourhood i would give you all the parts i pulled from a ‘59 when i did a big block/auto swap.
Bell,would work, but flywheel is off a poly. Different bolt pattern.
 
AJ is right. Your original 3 speed is small, light duty and non-synchro first. (3.09 first gear) The bolt pattern is completely different than the A833 and the newer all syncho 3 speed that was introduced in 1970 or so. A 3 on the tree shifter is far from precise. It may be fine for puttin around town but terrible if you get in a hurry. Absolutely NO reason to consider using your original trans at all.

And after going to all that trouble, why a 3 speed? IMO, better to go 5 speed with OD right from the start.
 
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Gotta go with AJ on this one. A stock 239 has an effective torque curve of off idle to about 4500 rpm, a close ratio A230 with 2.94 gears would make a very nice cruiser and distance driver in an early A. I am all about keeping it real with the three speed, too, but I would definitely upgrade to an A230 close ratio. I did find this, Perfection OE Replacement Flywheels 50-3409. Being it works on the 318 as well, it is a neutral balance engine. It has been a while since I worked on one of these, so I had to jog my memory. All the 5 speeds are pretty large and going to require floor pan and cross member surgery. For someone doing a 5 speed, there is also an NP535/Nv2500 box that was close to AX15 size. It was used from 1987 to 1991 with v6 4X2 or 4X4 and light duty 318 4X2 truck and van service with removable bell housing with ratios of 3.79, 2.29, 1.48, 1:1, 0.79 OD, and a 3.90 reverse. But to me a five speed swap takes away more than it would give back, just be too much like getting the whole Dakota/Van/Pick-Up as a driver.
 
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Yes, crank sensor, locked distributor with cam sensor, EFI, etc. Put the v6 reluctor and cap in and on a V 8 distributor with a good curve set up for the vehicle, a 500 cfm Holley two barrel, and an electric fuel pump and enjoy.
 
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Garrett Ellison said:
Gotta go with AJ on this one. A stock 239 has an effective torque curve of off idle to about 4500 rpm, a close ratio A230 with 2.94 gears would make a very nice cruiser and distance driver in an early A. I am all about keeping it real with the three speed, too, but I would definitely upgrade to an A230 close ratio. I did find this, Perfection OE Replacement Flywheels 50-3409. Bring it works on the 318 as well, it is a neutral balance engine. It has been a while since I worked on one of these, so I had to jog my memory. All the 5 speeds are pretty large and going to require floor pan and cross member surgery. For someone doing a 5 speed, there is also an NP535/Nv2500 box that was close to AX15 size. It was used from 1987 to 1991 with v6 4X2 or 4X4 and light duty 318 4X2 truck and van service with removable bell housing with ratios of 3.79, 2.29, 1.48, 1:1, 0.79 OD, and a 3.90 reverse. But to me a five speed swap takes away more than it would give back, May as just get the whole Dakota/Van/Pick-Up as a driver.
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I like what you're saying,
but the 65 Valiant combo is likely to come in under 3000 pounds.... as compared to say 3600with a 2wd Dakota.
That makes the 3.9 come alive with a starter gear of say 2.76x3.83=10.57, and the hiway gear becomes 2.76x.79=2.18.. so 65mph becomes about 1800.... me likey. Ima thinking that could be tuned into high 20s mpg
 
slantsixdan said:
Y'oughtta put together the world's first and only 3.9/5-on-the-tree '65 Valiant. I'm just saying, is all.
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We can do it!!! A little oil hardening plate, rods, and,.....well, a custom short-throw shift lever....if You like Your knuckles........:rolleyes:
 
Again, thanks you for all the posts.
I’m wanting to keep the original trans, just because this will be an occasional driver. Yeah, it’s an inferior tranny, but that will make it all the more unusual too. I’m going for the one of a kind A body. Tons of slants and V8s that look and perform really awesome. My Dad’s being an example, 416 stoker 340, 4 speed, 8 3/4”.....I like something that hasn’t been done. I wanna turn heads and have people doing double takes when they see my car..”was that a....dis you see....”. That’s me.
Keep it coming people, I need all the input I can get.
 
Take the cover off that 903 trans and look at those puny gears designed for a 170 cuber. And then look at the inside-out puny synchronizer rings, and the puny slider. And the puny shiftforks. and the unsynchronized low gear that slides on the puny mainshaft splines.
You'll get no love from anybody as regards being different for using that lawnmower transmission.
After you have found a suitable bellhousing to use and adapted it to the 903, and forgot that you cannot (easily) downshift into first gear,and the cluster is now laying on the roadway...................
 
Has anybody change out the Dakota 5 speed stick to something more sporty looking? Is that tranny a toploader type? Just curious.
 
Absolutely, I can’t think of a single reason not to upgrade to an a230. I have an uncle with one from a ‘72 340 demon that I have nearly talked myself into needing in my project. I know of a lot of 230’s used in oval dirt and asphalt, even behind big blocks and not breaking.
 
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