Magnum motors

-
chlngr1970

chlngr1970

Well-Known Member
Joined
Oct 5, 2008
Messages
1,675
Reaction score
154
Location
Sultan WA
So, I scored a 5.9 Magnum/Auto/9.25 rear from a 2K Dakota R/T. The 5.9 will fit nicely, in my 98 Dakota Sport 4X4. I MIGHT even put the 9.25 in the Dakota as well. So, I've seen where the Magnum motors have been dropped in our A-Bodies. I am giving serious consideration to taking the 5.2 from my Dakota, mating it to the tranny from the R/T and dropping it in my Demon. The drive train comes with both the stock R/T computer, and a MP computer. What I am thinking of is, picking up the Edelbrock Airgap intake, and maybe putting in a nice cam. Think it would be possible to get about 350 HP out of it?

j
 
Just so you know, that trans. won't just "drop" in your Demon. You'll have to do quite a bit of work to make it fit. It's a lot fatter and longer. It'll also require the use of the PCM to control the trans. Which one are you asking about getting 350 hp from?
 
fishy68 said:
Just so you know, that trans. won't just "drop" in your Demon. You'll have to do quite a bit of work to make it fit. It's a lot fatter and longer.
Click to expand...
Yeah, I know...but I've been toying with the idea of an OD for a while now, and this just happened to fall in my lap. I'm torn because the floor pans are in such good shape, I don't want to cut them LOL!

It'll also require the use of the PCM to control the trans.
Click to expand...
This is something that either the stock computer, or the MP would do, right?

Which one are you asking about getting 350 hp from?
Click to expand...
I'd like to get 350 HP out of the 5.2. I figure with a bigger cam, the Hughes/Edelbrock intake, larger throttle body, bigger injectors, headers, 2.5" exhaust, and maybe some head work, I can do it.

j
 
chlngr1970 said:
Yeah, I know...but I've been toying with the idea of an OD for a while now, and this just happened to fall in my lap. I'm torn because the floor pans are in such good shape, I don't want to cut them LOL!
Click to expand...
Screw the floor pans!

This is something that either the stock computer, or the MP would do, right?
Click to expand...
Yes, that is what he's talking about.

I'd like to get 350 HP out of the 5.2. I figure with a bigger cam, the Hughes/Edelbrock intake, larger throttle body, bigger injectors, headers, 2.5" exhaust, and maybe some head work, I can do it.

j
Click to expand...

Easy on ethier engine.
Click to expand...
 
chlngr1970 said:
Yeah, I know...but I've been toying with the idea of an OD for a while now, and this just happened to fall in my lap. I'm torn because the floor pans are in such good shape, I don't want to cut them LOL!

LOL... I know exactly what you mean. I'd love to have O.D. in my Cuda but the floor pans are original and near perfect and I hate to cut them. I think in your case since your thinking of using the 5.2 I'd try to see if I could swap the A518 for an A500. It's plenty strong and would require a little less floor pan surgery and won't consume as much power as the 518. Just a thought.
Click to expand...

This is something that either the stock computer, or the MP would do, right?

Yep, like Rumble said.
Click to expand...

I'd like to get 350 HP out of the 5.2. I figure with a bigger cam, the Hughes/Edelbrock intake, larger throttle body, bigger injectors, headers, 2.5" exhaust, and maybe some head work, I can do it.

j
Click to expand...

That's a nice intake setup Hughes has. Pricey, but if it delivers what they say it's a real nice improvement over the stock beer keg intake. I agree with the other guys that it should be no problem getting 350 out of it with those mods.
 
Well, with the 5.9, I'm looking more for troque, as I'm gonna be using the Dakota to pull my Duster and Demon around on a trailer. First to the body shop, then when I can, to the track :) That is also why I will probably swap the rear into the Dak as well.

As for the 5.2...I don't have a lot of experience with modern FI motors. WIll I need a Cattalitic converter, or can I just dismiss that? If I do need it, do they make one that would kinda work like an X-Pipe? Thoughts flying through my head ATM. Gotta collect them so I can get a plan together to at least get the Demon on the road soon. :D

j
 
I'm not sure it is a must. Alot depends on if the computer runs 2 o2 sensors, one before, one after the cat. Now dont worry about a cat being there..... the after market makes high flow cats for over 500 HP power plants and they also can be had with 2 pipes in, 2 pipes out. Not exctly a X pipe system, but, the thought is there.
 
So, I brought home the motor, trans and rear end yesterday. About to go unload it and take some pix :) I got the two computers along with all the connectors for each sensor/controller/whathaveyou, that was removed from the R/T wire harness with about a 3-4" pigtail. I was told the plan was to ship the pigtails off to a place that makes harnesses for your car. Anyone know if that exists? If so, any experience with them? I wanna move forward with the plan of putting the 5.2 in the Demon. Does the 5.2 use the same type of headers as an LA motor? I can get that ordered in the next couple weeks, and get the car ready to be fitted with the OD tranny while I wait for the harness to be built, and get the motor swapped into my Dakota :D

j
 
The only place I'd know to check is www.evanswiring.com They sell wiring harnesses for our old iron. Don't know if they'll do a custom harness but it's worth a shot. If they don't maybe they can recommend a place. Yes LA headers work.
 
OK, cool. Depending on the weather next week, I'll probably swap the front end off the Duster over to the Demon, and maybe even get the rear brakes rebuilt. I gotta pull off the bumpers and lights, pretty much everything that would have to be masked off when painting the car. Do the LA motor mounts work on the Magnum blocks? Should I swap in the 73-6 K frame, or keep the factory V8 K Frame? Will spool mounts work better with the magnum? Will it make a difference?

Once I get the motor and tranny in, I'll order a new radiator with the correct inlet/outlet location to match the water pump on the magnum.

Fuel pump...can someone recommend one? Will an inline pump suffice, or will I need an in take from a Dakota? If I need an in tank, how hard is it to adapt that to an A Body tank?

Lots of questions... LOL

j
 
chlngr1970 said:
Fuel pump...can someone recommend one?
j
Click to expand...

I am just now installing an EFI type pump in my 65 Dart. My tank sender has a 3/8" outlet and 1/4" return tube. I ran a new 3/8" steel line and use the factory 5/16" line for return. I mounted a Walbro-type electic pump just above the left motor mount after a 3/8" metal filter. The pump has 10mmx1 internal threads. Many adapters available. I used the 3/8" hose nipple ones, along w/ mount straps (ebay store). Following that is a filter/reg used on Corvettes (33737, $20 at O'Reilly's), which bypasses at 58 psi.

The other external EFI pump you see a lot is from 90's Ford trucks. It has a 5/16" quick-connect male brass fitting in the outlet. I have seen no other fitting choices there. The inlet is large plastic external thread. I have seen 3 different brass fittings for it - 5/16 quick male, and ~7/16" and 1/2" hose nipples. Could be tricky to adapt to 3/8" hose or tube. I use that type pump w/ 5/16 hose in my Newport. Similar (or same) pumps are sold under MSD, Accel, Holley,etc names.

I also have a Bosch EFI pump from European cars but impossible to plumb since a 12 mm threaded outlet w/ banjo-checkvalve fitting and a ~1/2" tube inlet.

Re regulators, early Magnums had one at the rail w/ 3/8" inlet and 5/16" return. Later Magnums (~1997?) are returnless w/ 5/16" inlet. The reg is in the tank. That is why many use the Corvette reg, great price plus a filter. It has a 3/8" female quick-connect outlet. I had a piece of male tubing that snapped in (from early Magnum). I reduce to 5/16" tube to connect to a later Magnum rail.

Initially, I am using a carb, so another 10 psi relief plus a reducing reg. Later, I plan to switch to Projection TBI, which has an internal 22 psi reg. Eventually, I plan to install a Magnum intake to realize MPI.

Hope that helps. You will likely spend more for fittings than the pump, and will probably run into many "can't get there from here" plumbing problems. I was amazed that quick-connect fuel fittings are rare. I assumed ubiquitous. Seems only GM and Chrysler use them. I prefer them to hoses and clamps at >40 psi, but can't spend my life designing the plumbing.
 
Here is what I have:

  • 1998 Dodge Dakota 5.2 Magnum
  • 2000 Dodge Dakota R/T OD transmission
  • All the connectors to build a harness ( the next big step )
  • a 1971 Dodge Demon to put it all in :D

I'm already looking at getting the short block gone through to make sure it lasts more than a few days.

One thing that I thought of today, will I need to use the instrument cluster from a Dakota to make this work? Specificly, I know I will need some sort of CEL, but what about the odometer, where the engine codes can be pulled up at, and the OBDII connector. I didn't look to see if the OBDII connector was in the canisters or not, but I'm pretty sure I can get one from the wrecking yard...

more questions later...

j
 

Attachments

  • 59 magnum.jpg
    72.6 KB · Views: 542
  • 59 magnum 2.jpg
    74.1 KB · Views: 543
  • Auto OD trans.jpg
    58.9 KB · Views: 527
  • Auto OD trans 2.jpg
    58.7 KB · Views: 553
chlngr1970 said:
OK, cool. Depending on the weather next week, I'll probably swap the front end off the Duster over to the Demon, and maybe even get the rear brakes rebuilt. I gotta pull off the bumpers and lights, pretty much everything that would have to be masked off when painting the car. Do the LA motor mounts work on the Magnum blocks? Should I swap in the 73-6 K frame, or keep the factory V8 K Frame? Will spool mounts work better with the magnum? Will it make a difference?

The magnum's have the LA style mounting ears but you'll have to find the brackets that bolt to them. The 73-6 K-frame has one advantage, the motor mounts (spool type) are basically unbreakable, unlike the 72 back but if it already has a good K-frame I'd just put a set of Schumaker Iso-locks in it. Their a locking mount that replaces the weak factory mount. They aren't cheap (about $160 a set) but it's tons less work than swapping a K-frame and they work great.
Click to expand...

Once I get the motor and tranny in, I'll order a new radiator with the correct inlet/outlet location to match the water pump on the magnum.

Your stock V8 Radiator should work fine as the inlet/outlet are in the same locations and same sizes.
Click to expand...

fuel pump...can someone recommend one? Will an inline pump suffice, or will I need an in take from a Dakota? If I need an in tank, how hard is it to adapt that to an A Body tank?

Lots of questions... LOL

j
Click to expand...

I was just looking through the new summit catalog today and see they have numerous fuel pumps for engine swaps like yours. They have in tank designs and external types. In tank is neater but more hassle if something goes wrong. You just need to find out what pressure it runs at and get one in that range that mounts the way you like. If you do run an external make sure it's no higher than the tank. Electric pumps don't like to run dry, even for a few seconds. BTW: I had a 93 Dak and if I remember right it ran at 45-50 lbs. I don't think they changed much of anything in just 2 yrs. so it's probably the same but double check to make sure. Since your going high perf. you might even be able to up that some.
 
fishy68 said:
I was just looking through the new summit catalog today and see they have numerous fuel pumps for engine swaps like yours. They have in tank designs and external types. In tank is neater but more hassle if something goes wrong. You just need to find out what pressure it runs at and get one in that range that mounts the way you like. If you do run an external make sure it's no higher than the tank. Electric pumps don't like to run dry, even for a few seconds. BTW: I had a 93 Dak and if I remember right it ran at 45-50 lbs. I don't think they changed much of anything in just 2 yrs. so it's probably the same but double check to make sure. Since your going high perf. you might even be able to up that some.
Click to expand...
Good info there. I'll get those mounts ordered next week. I will also look into the 98 Dakota 5.2 pressure. I'll probably run an external fuel pump to reduce complexity of the system, and allow the possibility of easier maintenance. I'll probably also order up the headers, and pick up the parts for the Evap emission control system. So far, I can't find much on the retro side of the Fuel Injection system. Most people seem to switch over to carbs instead of trying to put the FI in :(

More later...

j
 
chlngr1970 said:
Good info there. I'll get those mounts ordered next week. I will also look into the 98 Dakota 5.2 pressure. I'll probably run an external fuel pump to reduce complexity of the system, and allow the possibility of easier maintenance. I'll probably also order up the headers, and pick up the parts for the Evap emission control system. So far, I can't find much on the retro side of the Fuel Injection system. Most people seem to switch over to carbs instead of trying to put the FI in :(

More later...

j
Click to expand...

Yep, most do away with the F.I. I figure it's because switching to a carb is so much less work and cheaper.
 
after doing a bunch of EFI retrofits, i have some advice for you.

1. pick up a complete engine/ecm harness from a wrecker, and a good wiring diagram. most factory EFI systems only need 3 or 4 wires from the recipient car to run. fairly self contained. youll spend more time making it neater and getting rid of unneccessary crap. if i remember right, the magnum setup requires 3.

2. go in tank. the pressure is more stable, the pumps run cooler and last longer, and they are a BUNCH quieter. i usually run a GM L98 tpi pump, as they work and are cheap. also, i typically plumb with hardline for most, and AN pushlock for the flex lines.

3. run a high flow cat.

4. get a good code scanner. since youre OBD2, that will be difficult, but theres stuff out there for your laptop that works great.

hope that helps.

Michael
 
dusterbd13 said:
after doing a bunch of EFI retrofits, i have some advice for you.
Click to expand...
Reading intently LOL

1. pick up a complete engine/ecm harness from a wrecker, and a good wiring diagram. most factory EFI systems only need 3 or 4 wires from the recipient car to run. fairly self contained. youll spend more time making it neater and getting rid of unneccessary crap. if i remember right, the magnum setup requires 3.
Click to expand...
Constant, and switched power, and ignition by chance? If I can get my better half to buy into my plan, I saw a 5.9 with harness on CL for $400 with a cracked block. I have seen where just the harness goes for over $200, so the extra accy's and other parts off the motor would be a bouns.

2. go in tank. the pressure is more stable, the pumps run cooler and last longer, and they are a BUNCH quieter. i usually run a GM L98 tpi pump, as they work and are cheap. also, i typically plumb with hardline for most, and AN pushlock for the flex lines.
Click to expand...
Like this from Oreilly's?

3. run a high flow cat.
Click to expand...
Should I run two with dual exhaust, or single, and Y it in and out for that dual look?

4. get a good code scanner. since youre OBD2, that will be difficult, but theres stuff out there for your laptop that works great.
Click to expand...
I need to get one for work anyway, so maybe I can use it as a write off LOL

hope that helps.

Michael
Click to expand...
Tremendously! TYVM!

j
 
yup. i personally prefer bosch or walbro, but have used airtex before.

and like i said, its been quite a few years since i did a magnum, but i believe that there are 3 wires, switched, constant, and ignition. have to look at a diagram to be sure, though.

i found when doing my 5.2 dakota that it liked a 3 inch single better than split or true duals. YMMV though. completetley different animal youre going for there.

Michael
 
Alright I have a 1972 Plymouth Scamp originally slant six 3spd auto, I have a 5.2L magnum motor out of a 1995 Dodge Dakota w/ complete wiring harness, fuel pump computer i mean everything, i also have a 1992 A518 lock-up OD tranny

I know that I have to widen crossmember to accept transmission, which is no problem as I have no floors in it now, I am also taking out the trunk pan out and replacing it w/ a flat piece of metal (getting rid of spare tire hole= flat surface for fuel tank) and installing a tank from a ramcharger w/ MPFI motor to take care of fueling issues. The transmission is a lockup overdrive meaning it will only need the shut off switch and wiring to the computer which i have, i am also replacing the rearend with an 8.8 locker rear from an explorer

So I think I have have confronted most of the issues brought up in this discuusion, I was wondering if you guys know anything more that I may not know that woud help me to get this motor in i would greatly appreciate any info, Thanks

Some questions that I am looking for answers for: Motor Mounts?, Driveshaft?, Vaccum issues (Do I use Dakota Power Brake Booster?)
 
nope. use the duster booster.

and i believe magnum mounts and LA mounts are the same for motor mounts. so use the conversion brackets for the LA to slant 6.

drivehsaft: with an 8.8 and an overdrive auto, you WILL need to have some work done. wait till everything is in, and measure it up.
 
Fishy is right. The motor provides vacuum for the booster. One question I did come up with tho, will I need to change my manual steering, or do I try to bypass the PS pump with a NON PS setup?

j
 
You must log in or register to reply here.
-

Back
Top