I have a 85 Dodge W350 with a 360 Carb engine and the truck has a NP435 manual transmission and 4x4

I am wanting to swap the original 360 carb engine for a 96 engine that is a 360 Magnum with fuel injection

My goal is to get much better fuel economy with this swap and also because ,y original engine has a cracked block, now would be a good time to do this swap if it's possible.

I am making this post to gather info about how to preform this swap and what all I need to do to make this swap work.

I an aware that the 360 magnum engines do have the mounting ears to put the 80's engine mounts on the 360 magnum engine, so I know the engine will fit into the truck, but I need details about how to match up the engine to my manual NP435 transmission.

I know that I will need to install a fuel pump in the tank for higher fuel line pressure and thats not a big issue. I also know that I will need the computer and engine electrical harness out of the truck that the magnum engine comes out of....But what else will I need to do to make this swap work.

Others with info, Please help me!

~Thanks, Tom

 

You will need a flywheel for the magnum motor, I doubt they are the same between the two. Then you will need a pilot bushing for the np435 that you may need slightly machined down to fit into the magnum crankshaft. You will also need to notch the 435 bellhousing to accompany the crank position sensor that sits on the back of your magnum 360. A clutch disc for a 435 will need to be matched to a pressure plate for a magnum 360 flywheel, unless you'd rather re-drill the flywheel. For example, the magnum flywheel can take up to a 12" clutch, so any 12"x1 1/2" clutch disc will match up to a pressure plate designed for the same dimensions of friction surface. Other then that, as long as the pilot tip of the input shaft sits correctly in the bushing, I think it's all electrical stuff. Good luck and keep us updated!

 

Ok, so the original 360 LA engine in the truck uses a Quadrajet Carb...

My whole goal here in to increase my MPG fuel econemy by going from a carb to EFI.

Also, I'm wondering if it would be better to use an OBDI or OBDII engince for this swap?

My truck was custom fuel tanks build under it, so installing an electronic fuel pump in the tank is not a problem.

Also, wondered about wiring for the dash gauges...The Spedo is cable so thats not a problem as I am gonna use the original NP435 trans that has the spedo cable attachment. But, I did wonder about the other gauges such as engine temp, oil pressure as they are run thru the computer on the magnum engines? would I just splice the gause outputs into my original dasg gauges (ie, is it that simple?)

I see that I will have to notch the top of the bellhouseing to allow room for the sensor and thats ok to do...

Just want more info about doing the swap and the electrical. I'm very good with electrical, just wanna get an idea of what all it will entaile so I dont forget and overlook something.

I gather, that I will use the computer out of whatever truck I pull the engine from and the wiring harness from the magnum engine to the computer. But what about the computer outputs to the gauges?

As for the other side of the electrical system, I do plan on pulling a fuse box and doing pretty much a full rewire of my truck to do away with the fuse links and instead use a current fuse box with ATC fuses, so I will tie the computer into the newer fuse box and supply power to the truck and computer from there.

So, anyone with input about the guages?

Also, I wanted more info about the clutch setup...I have read others posts about swaps, but they were all about automatic trans....In my situation, I am using a Manual trans (NP435), so there is no torque converter and so I guess the stuff about the balancing the flexplate/converter does not apply, as the magnum "should" directly bolt up to the bellhousing with no problem, just want more info about the clutch setup.

I notived that the magnum 360 uses a 12" clutch and the original 360 LA uses a 10" clutch, so is it really as simple as drilling the magnum flexplate to accept the 10" bolt holes? or what else is needed??/ Alot more info about this would also be very helpful.

As far as the exhaust manifolds, I know the LA is a center output to the pipes and the Magnum is a rear output to the pipes, so I will have some minor plumbing to change to get the exhaust pipes to mate up with the change in exhaust manifold output location.

-Others, please provide any input for this swap, as the info I have found thus far in my research of this project is mostly about swaping and still using a carb and Not the EFI and also about auto trans setups, So I want to address these points because I want to use EFI on the magnum to increase my MPG and also since my truck is a manual trans and not an auto trans.

 

You might be better off using a standalone fuel management system, then wiring your gauges in the manor used in '85.

Magnum's used an 11" clutch from the factory. Heres a possible 10.5" setup.

http://www.summitracing.com/parts/MCL-610991/ - designed for 1996 ram w/v8
http://www.summitracing.com/parts/MCL-260120/ - designed for np435

So then all you'd need to do is call Mcleod and ask if the friction surfaces line up. I would guess that they probably do.

 

making your gauges work should be simpler that baking pizza. all the gauges share a power supply. the only thing that changes is how much resistance there is between the gauge and the ground connection. the higher the oil pressure the less resistance there is at the sensor which makes the gauge rise. almost all the gauge work that way except for the amp gauge. power need to pass though it to make it work and if you are rewiring you may just want to disconnect it.

if you are going to do the swap don't even waste your time with obd1. go with at least obd2 so the you could at least custom tune the computer if you decided to start modifying it.

 

I just wanted to be sure that there wouldnt be any problem with the gauges other than finding the right resistance. If needed, I could add a resister inline with a gauge if needed.

As for the fuel managment system, what do you mean? Do you mean having the gauge wired directly to a fuel level sender in the tank or what? (As for the fuel sender, I already have that portion covered for the swap as I have dual custom tanks with a tank selector switch that has a crossover for the fuel level sender, so I can just drop my tanks and insert the electric fuel senders into the tanks to raise the fuel line pressure up to the needed 45 psi range, as compared to the current 15 psi for the carb) But is that what you meant by using a fuel management system or what?

And between going with an OBDi or OBDII engine, I just wanted to know which would be easier to work with.

As I said, my main goal here is to increase my MPG, so anyone got any guess of what the new MPG would be by doing this sway to EFI with the magnum engine? Or will it be pretty much the same as the MPG of the truck that the engine comes out of?

Currently, the old 360 with the Quadrajet carb only gets me about 7-8 mpg and I'm really wanting to get that number up with the swap to a 360 magnum with EFI.

 

you should not have to add any resisters. the sensors that come with the 96 block should work fine with the stock gauges. this might help you understand. you may also want to upgrade the voltage regulator on the back of the gauges.
http://www.allpar.com/history/mopar/electrical2.html

i think when 2x1972 mentioned fuel management system he was talking about getting an independent computer to run the engine. if you use an independent fuel management system then you will not have to go with a obd1 or obd2 system.

it sounds like your carb might be a bit out of tune. if your carb was setup correctly you should get getting better than that.

 

Yea, I get a solid 12mpg in my '72 with a small 4bbl (carter AFB) and longtubes, and that's sitting on 39" honkers. My 318 with just those mods is obviously set up for optimum efficiency, but with near 40" of rubber that kind of nullifies that fact

 

My truck is low on MPG partially because of the truck bed/body is heavy steel, so thats where alot of the mpg is going into hauling the extra weight around, but that cant be changed because of what I use the truck for..

As for the fuel management system and OBDi/OBDII, this is where I'm kinda at a loss of what yall mean. Aren't I gonna use the computer out of the 96 truck to actually run the engine?? which would include the computer running the EFI..and since the computer is an OBDII setup, wouldnt that mean that the entire setup is that, an OBDII?? Or is the OBDII seperate from the EFI computer control of the engine? I know the OBD is the diagnostic part of looking at the sensors and the engine preformance, but again, aren't I gonna use the 96 computer to run the engine and EFI or is there some other aftermarket setup that I would use to run the engine and EFI instead of using the 96 computer?

 

if you go with a fuel management system like 2x1972 mentioned you will not have to use the computer from the 96.

if you use the computer from the 96 you will not need an independent fuel management system. i think if you were to use the computer out of the 96 it may always have a check engine light on if you decide to hook one up since there will a couple sensors not giving the computer input.