I'm kind of disappointed in the lack of info on this board on early first gen Dakota Magnum 318 swaps. I've spent the last three days doing the research, figuring out, for the most part, what is needed and what can be gotten away with.

What I've found is:

Mid 1980's 360 head, intake manifold, and carb equipped 318 squad cars switched from the 727 to the A998. The reason is, the heavy duty tranny wasn't needed, the A998 has 5 discs in their clutch pack compared to the A904's 3 disc clutch packs, allowing the A998 to handle higher torque loads. Keep in mind, all of the 235hp 320ft lb old school 318's used A904's. Having owned a mildly modded '72 Challenger, I can contest to the amount of abuse a good A904 can take, just so long as you use a good aftermarket tranny cooler.

All this means is that 1st gen V6 Dakota owners can retain their trannies and kickdown linkages, with the change of the flex plate, giving them time to find a 46H (Hydraulic A518) and corresponding kickdown linkage and driveline.

The V6 mounts are reusable.

An electric low pressure inline fuel pump is needed, because Magnum engines aren't designed to use a mechanical fuel pump.

LA manifolds are interchangeable with the Magnum heads, opening numerous options, if you don't mind tunning and using a carburetor.

Electronic ignition is pretty straight forward, Mopar dizzy and MSD or an a like control box to handle ignition curve duty.

The most complicated thing that will be encountered is, some custom rewiring. I suggest using as much of the original factory harness as possible and splicing in and adding to when needed.

An electric pusher fan mounted in front of the radiator is mandatory, because there is no clearance for a mechanical fan.

Use a 93 Y pipe, '92-'95 cat and what ever cat back exhaust suits your fancy.

The front springs and anti-sway bar needs to be changed out for V8 units.

The only thing I'm unsure of is, which accessory bracket set is needed.

Everything else has been covered and has plenty info on the matter.

If anyone has something else to add or objects to anything what was mention above, feel free to share your two bits.

-Joel

 

Low pressure?? The magnums run about 40 psi of fuel pressure for the injection system.

Are you talking about intake or exhaust manifolds? If intake, I don't believe they are interchangeable. If you can disprove me, please do, but I've always heard they can't be swapped out.

The magnum accessory brackets need to be used. The LA accessory brackets won't bolt up to magnum heads.

Otherwise, good info! If you're planning this swap, please do a detailed write up lots of pics! We always want to expand this forum!

 

The lack of info is due to NO ONE has done the swap!!!
If you do the swap DO A DETAILED write up on what to do and Pics. That way others will have the info, and then no one else can be disappointed.



No they are not interchangeable. The Magnum bolts are vertical. LA are set in at an angle. Same it true for Chevy and Vortec heads.

 

If memory serves me right, the intake mounting surface angle on the Magnum heads is the same as the LA series heads. The EGR ports are in different locations, but in my area of the country, we still can get away with not having EGR. I could run a different style of EGR that uses a conection straight off the exhaust pipe somewhere to an off board EGR valve

From what I have been told from the guy behind the counter at the local Carquest around here, he and his father installed an LA head style intake manifold on a magnum series engine in his father's '71 Cuda project car. He said that there a couple of things he said you have to watch out for. First, the LA series manifold will cover up the EGR ports in the Magnum heads, causing the engine to run a little ruff. Second, you will need to redrill the bolt holes to accommodate the Magnum's different intake manifold bolt angle. You can use a short piece of steel pipe with the bottom cut off at right angle to match the angle of the intake mounting flange to apply the necessary force of torque across the flange to provide an adequate seal. If need be, you can always purchase a magnum series carburetor style intake manifold that quite a few aftermarket suppliers offer, such as Mopar, Edelbrock, Weiand, etc.

The biggest difference between the LA and the Magnum series engines, apart from the INTERNAL design and dimensions of the heads, are the oil delivery systems in the blocks. The LA engines oil the heads by pushing oil through holes in the cam, up through a passage that leads up from the holes in the cam into the head, up to rocker shafts. From there the oil flows to the rockers and back down through the push rod and oil passages, down to the cam valley, where the oil encounters a series of openings in the cam valley and then through these holes, drips oil down into the crank case.

The Magnum engines don't have the passage that leads up to the head from the holes in the camshaft bearing journals No.2 and No.4, instead they use the GM/Ford method of pushing oil up through hollow push rods to the rockers.

Yeah boy! I have every intention of doing the swap AND documenting every last detail for people in the future to use, if they so desire to follow along this path.

I have found that the early Dakotas are the underdog of the underdogs. Dakotas don't get a lot of recognition in the truck and wheeler community, but the early Dakota's don't get a lot of recognition even within the Dakota community, despite their slightly greater advantages in certain areas.

 

Magnum intake mounting bolts are vertical. Look at the blue arrows.


LA intake mounting bolts are at an angle. Look at the red arrows.


For the differnce inbetween LA's and Magnums check out here. http://www.allpar.com/mopar/318.html