Has anyone put a 3.9 v-6 in an a-body?

I realize "why" would I want to put a v-6 3.9 from a Dakota in an 64-66 a-body?

I'm just looking to see if anyone has and what is the biggest challenges? I have a 80k f.i. v-6 that runs great and I am thinking about dropping it in with a 904. Cheap fuel injection, not too fast for my son and reliable. Plus room to turbo if we choose. Just looking for advice.

SN: I don't want to drop in a v-8 as he is a young driver. A 3.9 engine is a good engine for a young man to learn to go thru, room to drop in with ease and more power than a slant 6 but not too much to wrap around a pole God forbid. If it was just me a new 5.7 hemi would be shoehorned in.
Thank you,
Joe

The v6 is going to be harder to drop in than a V8 as you will need to make your own motor mounts and if you want headers you will make them also. I doubt the magnum manifolds will fit an early A body, they barely fit the later A bods.

A 273 is a bolt in, don't make too much power and can easily be swapped for a 318 340 360 or even a 408 later when he is ready to lose the training wheels.

All obstacles aside I would do it if I was planning it to be the permanent engine because I like things different. I would not go through the hastle if the long term plan is something bigger eventually.

With both the six cylinder and the 273 comments. Although, isn't the 3.9L similar to a 318, just 2 less cylinders (read from Allpar). The only way you'll know is if you test fit it. Although, I'd rather see the six cylinder in there.

It is a 318 with the two rear cylinders cut out and the motor mount ears cut off.

You can not just hack two tubes off the headers as the exports are out of sequence, there are no headers off the shelf for it, the TBI/Carb manifolds bit and will hit the steering so you are stuck with the rear dump magnum manifolds and even they may not clear the firewall.

I would consider a swap of this nature, but only if I was swapping the entire drive train, including the overdrive trans. I've done a 5.2/A500 swap into an '84 Ramcharger. Motor mounts are not a big issue, but I would start by putting the engine bolted to a 904 so that you can get the trans in the correct place. Then build mounts and add the OD (will need floor mods). Use the entire electrical from the donor vehicle (OBDI is easier to deal with than OBDII) and go from there...

what's wrong with using the slant six? they can be pumped up and still not worry about on coming telephone poles! plentiful and cheap. i know it's not what you asked but i was considering doing this for my son until he rode in a jacked up Jeep!

I'd just slap in a 318 2-barrel, a totally stock one. Honestly, it's probably still going to be slower than my 2012 1.4L, 138hp Cruze. Especially with tall gears. Makes about the same HP as a stock 3.9 Magnum anyway.

I've thought about a swap like this too, just because it is different. Unfortunately, a 63-66 A body engine compartment and trans tunnel suck for roominess. They are really difficult to fit exhaust on any engine besides a Slant. A stock Slant would fit the bill for low power, and is easily hot rodded later.

If you mount the front of the V6 in the same location as the 273 then the OD trans is shifted about 4" farther forward, putting the fat part of the tailshaft in a "roomier" area, roomier being relative.

You also put the stock V6 rear dump exhaust manifolds pretty close to where a stock V8 exhaust would dump.

You also move the rear sump oil pan forward.

It any of it enough to make it fit? Dunno, haven't found a cheap enough donor yet.

I agree here. I like the idea of alternative swaps but I wonder what sort of extension you'd need for the water pump and fan to reach the radiator! Maybe an electric fan would be better? You'd gain some handling balance in terms of the center of gravity moving slightly rearward.

Keep us in the loop here, this could get interesting!

I have/had a 90 and a 91 and a 93 Magnum 3.9 here. All 3 motors still have the motor mount ears on the block. The heads look to be standard small block with the back cylinder cut off (left side). Both heads are the same. The exhaust ports have the one cylinder separate then the two ports side by side, but off the shelf headers are non-existent.
I too would bolt the motor & trans together and set them where they need to be, then build your mounts as needed. The exhaust isn't going to be any worst the putting a V8 in there would be, the back exhaust pipe on the driver side is the one that won't be there, and the back cylinder is the issue with a V8 install.

It won't be as easy as swapping in another slant 6 or a 273, but it would be a great motor for an early A body. But really Dad, anything can be wrapped around a phone pole. Sometimes the lack of power will do you in. Gene

Good Morning Guys and ladies.

Thanks for the advice. Honestly the car has been a slant 6 since 66' and after my offenhouser dual 1 bbl swap and a bunch of money into the engine it is still a slow and lack of power 6 cylinder that hates this new fuel we have to buy here in New England at the pump. MY boy wants a Fuel Injected v-6 with a turbo. I think he is on to something as this is the way to go as a v-8 is heavy, hot on a summer day and no room for mods without modifying the car which is way to clean and straight to cut her up. Maybe secretly he wants to take on Crow from the 405... LOL! he's 13.

I agree with Poorboy as lack of power is not good but as a Dad, I can put anything in the car "I" want. It is not for me but my son who has little skills at 13 years old. By building what he thinks is cool (turbo v-6) together he will respect the car more than if I just do it and give it to him.

I personally don't want to just drop in a 273 or 360 like every other car out there. If I did, I would had just bought a crate engine and transmission with an 8 3/4 and drop it in. 2 or 3 car shows and the car just blends in and there is no pride for my son. The slant 6 in the car looks really cool now but just plain is boring even with the 2 air cleaners and HEI ignition. I get there are slant 6 people out there who love them to death. No offence, but there is better technology out there and I want to be part of that technology but it needs to be Mopar; no Chevy engines for me. Sadly the Mopar Fuel injection has not changed for the better in a lot of years. I'm only going to do the 3.9 because I got this 80k engine for free and it runs great. I thought of a v-6 3.3 from a mini van but have no idea how to hook up a transmission and the computer programming needed to shift it. As MoPar fans we are limited to the luxury of this like our Ford and Chevy friends. We have to run the alcohol added fuel from the pumps here in New England and it makes a mess of carbs, tanks and fuel lines. I want a just pull up to the pump and "fill it up" mentality. I will have to modify the fuel tank and that's ok - I own a welding and heavy equipment repair shop. The mounts and welding and fabrication is not an issue. I thought about the new V-6 from a wrecked Challenger or Charger but the prices for the wrecked units and no aftermarket conversion electronics makes it more trouble than its worth.

Also, just for the masses: If I reverse the manifolds from a older v-6 (pre 1994) I can dump the exhaust in front of the engine and mount a turbo in front of the engine (low hood clearance of the early a-bodies) and then one single pipe back over the driver side of the engine out the back of the car. Room for an inter cooler and plumbing loosing the 2 front cylinders. I've done some quick measurements and a turbo and electric fan will clear - tight but no issues and NO inner fender cutting.

Thank you for your help.
Joe

No offense dude, but we're all running the alcohol fuel these days, and if you're still having trouble with fuel lines and such, you're doing it wrong.

I would sooner turbo the slant with an aftermarket efi system than look at a 3.9.

What a bunch of naysayers! Wimps! You'd think he's trying to repaint the Mona Lisa.

It's a great idea and I think I'd start by looking at Dodge Dakotas and how they're set up. Maybe drop the A-body on a Dakota frame, even.

But put the engine in the place where everything fits the best and go from there. If you have the fab capabilities it will be made to work. Even moving the radiator back or forward has been done before, no big deal.

The kid is 13? That's 3 years minimum to get it all together, should be long enough.

Alcohol fuel? Everybody gripes about it, why shouldn't he have that luxury too?

Just do it.
R.

I run mine on the same Ethanol blend out here in CA. Mine runs fine. I know that I'm not lucky or special, just that many people claim that CA gas is even worse than what people get in other states.
A return system in your fuel line can make up for the fast evaporation rates.

Gonna need to fab an oil pan or at least run the steering linkage through the sump, doubt your gonna find a pan to bolt right in as the only one ever made is rear sump.

No offense sir, but if you can't get an N/A Slant to run right you'll have a disaster with a turbo/efi V-6.

Well first step would be to get the v6 running, before worrying about the turbo. In the past when doing swaps like this I have bolted the engine to the trans and bolted it down by the trans mount and fabbed my motor mounts from there. That sounds like something the OP can do himself. The exhaust he can figure out after he at least gets the engine bolted down. He's got a lot more room in that engine bay to turbo the slant than he does to turbo that V6, but that's up to him.

I actually think a hi-po 273 would be a really fun build for this car and would certainly be a good opportunity to teach your son how engines work.

Good Morning MoParts fans,

This is what I was trying to prevent. Long paragraphs OFF topic from what I need... just info If any one had done it and what to look out for NOT opinions on why I can't or what you think is good for OUR car.

First off I've had a slant 6 in this car since 1989 when I bought the car from the first owner and there was no alcohol fuels. I have no issues with getting it to run on E-85 or alcohol fuels just to be clear. I just am trying to prevent World war 3 with the Slant 6 guys and not insulting them. They are the many that keep this hobby going. I've run cam 2 in both my cars since 2005 at now $10.00 per gallon because of the fuel issues from sitting. Honestly the Barracuda gets like 1,000 miles a year and the Demon last year got 50 miles. Even with additives and draining the tanks I just want to get in them and drive and the non-ethonol fuels help me get to that ride faster with less issues / less stress. My issue is the slant 6 is not worth building in my eyes. I tried to upgrade it and it still is a slant 6 and nobody even cares to look under the hood at shows. It is very disappointing. Turbo a slant6? SURE, but why? The intake and exhaust ports are still too small. Some do it, yes but I can drop a small block in with a carb and make twice the HP and 1/2 the work load, just like the masses. Even a MPFI 3.9 stock makes 30-50 hp more than a six by it's self. Less weight than a /6 and more room for other stuff. Even having the weight back of the engine compartment is an advantage.

So I thank everyone who has replied with good information. I appreciate it. Those who gave me reasons not to do it, thank you for your opinion but we are still going to try it Anyhow. As for my son Anthony... I will do the best I can to help you accomplish your goals. This is a good example of life and how others will try to stop and crush your dreams and goals because of their short comings. You my son have vision and drive - all I can say is "Go for it." I am there to help -Love Dad.

A bit more exotic swap would to be mating a Mitsubishi 2L turbo to a BUILT Baby 904 from a 78-84 Challenger/Sapporo and with all the computer controls for that Mitz motor you'd have up to 500 + Horse. Very light, small in width and full of power. Set the computer controls down and have 175 to 200 HP and as your driving just tweek the settings and POOF Raging bull in a china shop.

Hope you are considering my advice as helpfull not as a way to talk you out of it, I am trying to make sure you know what is going to be needed before hand.

If 6 cylinder power is all you need the v6 will certainly make more, the heads can make 300 HP NA without touching them, the slant, not so much, perhaps 200. There are probably more intake out there to pick from with the slant but the v6 manifold can have the runners cut down just like you do in the v8 manifold. You can get some thick phenoilc resin and make your own plenum plate to keep heat out of the air from the oil. Bore the holes out for a V8 throttle body and port the TB. The heads can be ported and bigger valves just like the V8 magnum.

The 3.3 and 3.8 are gonna be harder to get a good manifold as you cant really get in it to port without cuttin it open. No RWD trans that I know of. Performance pistons are gonna be totally custom, so are rods. The V6 magnum can use anything the 318 can.

I'm with you on this one! Go for the 3.9. Turbo would be fun.
I have a 3.9 with a 5 speed in my 48 Plymouth business coupe, and I like it very much. That early A body is probably lighter then my coupe. Adding a turbo might be more fun then I already have with it. I expect a build thread with the turbo 3.9.....

My coupe was built with a 90 3.9, but it has been replaced with a 91 3.9, both were throttle body injection and ODBI which is very easy to deal with. My 93 Dakota has a Magnum 3.9 with an auto (4x4) and it has port injection (barrel intake) and ODBII, its a little more complex to deal with, but I can feel the difference in power between the two motors, the magnum is hands down more powerful then the non-magnum. The magnum is backed by a OD auto, in a standard cab, long box, 4x4, with around 155K, the 91 (and the 90) are in a shortened Dakota frame (both wheel base, and trimmed off rear at the rear spring hangers) with a steel 48 Plymouth business coupe body, caring all the Dakota cab & box floors, and interior. The 91 motor has 118K miles and is backed by a 5 speed. Both vehicles have 3:55 rear gears (coupe is a limited slip, the truck is open) & run 235 x 75 R !5 tires.
The exhaust pipe ends on the 93 exhaust manifolds (rear dump) are a lot bigger then the exhaust pipe ends on the 90 or the 91 exhaust manifolds.

What year is your 3.9? Gene

All the 92-93 manifolds are bigger, Jeep, V6 and V8, I have all threee types here, 94 they shrank them to between the 91 and 92 styles. If you want to try some of the big V6 ones let me know as they are for sale.

It sounds like a good idea but it won't be an easy swap.
For less effort and heartache you could drop in a similar power 318 and be miles ahead.

The 3.9 isn't that efficient.

If you've got your heart set on this swap then get all over it. let us know how the swap goes and feel free to ask for input along the way.

Better look again, I repeat THERE ARE NO NORMAL MOUNT EARS like the style common on every other LA engine, only the flat bolts to the side of the block. Since the block is now shorter the mounts would have to occupy the same space on the side of the block. I have 3 at my shop right now, 2 magnums and 1 TBI an NO motor mount ears on either side of any of them.