Any reason I shouldn't do it? (Dakota/Magnum V8 content and questions)

I need another project like I need a hole in my head, but most this one just seems like it'll be a cheap weekend one and done deal.

I've got a '94 Dakota that I bought a year and half ago to do weekend chores around my first house. It's a regular cab with a short bed, 3.9 A/T that is pretty much bare bones other than having A/C (that still works...). At 192k, the 3.9 runs excellent, but I've got a lust for more displacement.

I've stumbled upon an opportunity to get a 5.2 motor out of a '94 Dakota, as well as a 5.9 out of a '01 Ram for a combined price somewhere between $400-500.

I know that the 5.9 isn't a direct swap into my truck, hence the need for an OBD1 5.2 from a Dakota. From my research, it appears that if I use a 94/95 5.2 Dakota wiring harness or wire for the two additional injectors, I can swap the IM/TB/Injectors/Distributor/Fuel Rails and other sensor related crap onto the 5.9. I'd also need to use an ECU from a 94/95 5.2 or 5.9, and the Dakota oil pan and pickup from the 5.2. I'll also need to address issues with various coolant hoses and the radiator shroud.

Where I'm foggy is connecting to my existing trans. I know it will bolt up, but will the necessary balanced 5.9 flexplate mate to the torque convertor in my trans? If not, would the torque convertor from the donor 5.9 Ram work? If neither of those options work, what TC should I be after?

Also, how is my 42RH/A500 going to handle the 40% HP and 50+% TQ gains? How about if I add some bolt-ons down the line (probably just headers/exhaust, intake and Mopar PCM. Maybe a small cam upgrade too.)? During the swap, I'll probably add a TransGo shift kit and trans cooler. The truck will most likely just see some spirited around town driving, cruising, a burnout here and there, light hauling (no towing), and maybe some very rare trips to the strip.

All in all, it seems like I can get the basic swap done for hella cheap. I'll probably also drop some coin on the Hughes intake gasket fix, which will actually cost more than the 5.2 motor I may be getting...

Thoughts/opinions?

I hear the Dodge PCM doesn't like much in the way of bigger cams, etc. There is a nice Mopar intake but its expensive and doesn't bring much extra power, looks cool though. You'll need the bigger (A518?) trans though. The smaller unit is challenged with the 3.9.

Gearheadotaku wrote: I hear the Dodge PCM doesn't like much in the way of bigger cams, etc. There is a nice Mopar intake but its expensive and doesn't bring much extra power, looks cool though. You'll need the bigger (A518?) trans though. The smaller unit is challenged with the 3.9.

A bigger camshaft isn't high on the priority list for this swap, at least not initially. However, I too have heard that the old "SBEC" PCM doesn't allow for many big mods. The Mopar unit will probably suit my needs.

I've done a little research on the A500 vs A518 today, and it seems conflicted. It seems like most get it confused with the manual trans that goes behind the 3.9, which apparently grenades quickly when turned by the 5.9. I only found mention of one 5.9/A500 failure, but the truck was modded well beyond basic bolt-ons. The A500 was put behind the 5.2 in some Dakota's as well as full size vans and pickups. In those applications, it was seeing only 40 less TQ than the 5.9 I'm looking at using.

On the same topic, if you go back to 904 vs. 727, the 904 is apparently much more popular in high horsepower applications due to it's lower rotating mass and better gearing.

Regardless, I'll probably see how mine does with A500. If it fails, I'll either build it stronger or toss in a A518.

My 92 Dakota 5.2L has the A518 trans, I personally haven't run across an A500 behind the 5.2L Magnum, but they are probably out there. Try it with the A500, you can always change it out for the A518 when it dies. On the 5.9L, is the balance weight on the flexplate or on the convertor?

There is someone in our region that has a second gen Dakota 5.9L with either an GM style LS computer or a Megasquirt setup with LS coils. Either way he did away with the stock ECU stuff. His truck started out as a 3.9L V6 as well.

81cpcamaro wrote: My 92 Dakota 5.2L has the A518 trans, I personally haven't run across an A500 behind the 5.2L Magnum, but they are probably out there. Try it with the A500, you can always change it out for the A518 when it dies. On the 5.9L, is the balance weight on the flexplate or on the convertor? There is someone in our region that has a second gen Dakota 5.9L with either an GM style LS computer or a Megasquirt setup with LS coils. Either way he did away with the stock ECU stuff. His truck started out as a 3.9L V6 as well.

I do know for a fact that the A500 was the trans in the Shelby Dakota, which had the hopped up TBI 5.2. It looks like the 5.2/A500 combo was only used until 1994. I'm guessing maybe it went in some lighter weight/duty RWD 5.2 vehicles like stripped out Ram Vans and single cab pickups.

My A500 seems to be pretty healthy, so I'll likely use it behind the 5.9. I might add a TransGo shift kit to help it out a bit, as well as a trans cooler.

On the 5.9 that I should be getting, the balance weight is on the flexplate. 93-95 5.9 motors had it on the TC, 96+ had it on the flexplate. It looks like the only snag I might run into is the TC "bolt pattern". The pattern changed very slightly for 96+. Apparently, to mate the pre-96 TC to the post-96 5.9 flexplate, you need to slightly oval out one of the four FP to TC bolt holes to make it work.

The mopar M1 intake isn't pointless, but the way people use it is. It's built for big cams and raised rev limiters and 99% of everyone who's ever bought one just put it on a nearly stock truck with 4800 rpm upshifts and wondered why it didn't help.

The a500 is perfectly good for a stock small block.

You can actually use a v6 harness with a v8 if you add two injector circuits and lengthen some wires. Sometimes that's easier than finding a compatible donor harness to swap in, just depends.

The 5.9 has a specific harmonic balancer in front and in back it either has a weighted flywheel or if auto it has a neutral flexplate and a weight on the converter. You can actually buy a weight kit and template from dodge to weld the balance weight in the proper position on your torque converter, and it's like 15 bucks.

The 94 5.2 truck should be a magnum right? I'd use its engine harness and computer as a starting point and find a 5.9 ram computer.

Is it SBECII or FCC at that point?

Yep, 93 and up for the 5.9 is magnum iirc.

SBEC2 I think.

A stock 5.9 in a single cab shortbed auto 2wd Dakota runs high 14s stock, maybe mid 14s on good tires. That's BEFORE mods. I think you'll like it.

I doubt I'll ever get as far as putting an M1 on it. I'll likely modify one of my OEM keggers when I do the plenum fix.

At my local U-pull yard today, I found a barely picked over 1994 5.2 Dakota. I was able to get its fan shroud and the entire engine harness and as well as PCM. No luck finding a 5.9 OBD1 PCM, but I do know that a 5.9 will run with the 5.2 unit I scored.

I'll be using the A500 torque convertor with the 5.9's weighted flexplate. All I have to do is slightly oval one of the flexplate bolt holes.

Should be picking up the 5.9 tommorow, and the 5.2 in the next few days.