Magnum retrofit

[Monkeyed]

I've been tossing this idea around with varying degrees of seriousness; pulling out my 318 LA and installing a 318/360 Magnum. Induction, injectors, sensors, wiring, computer and all. Also thinking about the overdrive trans to go with it (though maybe not at the same time).

I've scouted out some potential donor trucks on the craigslost, just trying to visualize the finer details to it, such as powering the stock components, HVAC connections, mating exhaust manifolds to system, etc.. what would be left in, what could go :eusa_think:

I've read that the trans tunnel would need some massaging, the driveshaft would have to shortened, and the transmission mount would need some cutting and repostioning done. I think if I get the right year the car shifter will work? and using the trucks computer will avoid a lot of the reworking involved as far as a vacuum switch and throttle position, not sure about the speedo, if that's electric or gear driven. Would need to make an "OD off" button...

anybody know of anyone who's undergone this kind of thing before? Or know of anything I should beware of

 

[Mcfly68]

Depending on years...may have seperate engine and trans controllers...will need an aftermarket shifter..the shift rods wont fit in the tunnel with the bigger trans ( a rear cable shifter needed). Custom rear cross member, floor brace/upper cross member needs surgery and re-enforcement. again depending on years, some electric speed sensors are fully swap able to mechanical speedo drives. new drive shaft

 

[efriedrich]

anybody know of anyone who's undergone this kind of thing before?

Look over at FABO, the A body guys do it all the time, tons of good info.

 

[kkritsilas]

Mcfly68:

Might be worth your time to check out http://www.magnumswap.com/. They have a lot of different sections dealing with various aspects of this swap.

Kostas

 

[Bruceynz]

I am looking at doing the same, but I think I will stick with a standard 3 speed trans, am just thinking! Guy in NZ has a 360 magnum for sale, as per my post. Will my standard 318 904 handle a 360 or will I grenade it?

 

[Monkeyed]

I am looking at doing the same, but I think I will stick with a standard 3 speed trans, am just thinking! Guy in NZ has a 360 magnum for sale, as per my post. Will my standard 318 904 handle a 360 or will I grenade it?

If you're careful with it you should be able to get some miles out of it, eventually you might want to think about a 727 swap. I saw a '94 Ram with a good motor, but the trans is shot. Got me thinking,

 

[CMX360]

Some time ago I saw pictures of a green four door Aspen/Volare with a complete 5.9 magnum swap. It was a rat rod at best but still pretty cool. He used his factory shifter and I think he said he didn't have to change his trans mount. He did have to cut his tunnel though. I don't think he had any hood clearance issues either. I've priced having a drive shaft shortened and it's cheap (in my neck of the woods anyway). Someone should make a kit for this. Plenty of cars to do it to and plenty of 5.2 and 5.9 magnums out there in need of new homes.

 

[kkritsilas]

A magnum engine swap should NOT need a change to the trans mount unless moving to one of the 4 speed automatics. They are what make the trans mount and floor pan tunnel changes necessary. The Magnum engines mate up just fine with the A904/A727 families of 3 speed transmissions. Without changing the transmission, you also do not need to shorten your drive shaft. If you are putting in a 4 speed automatic, and don't drop the trans mount, the drive shaft angles get weird, and from what I understand, beats the U joints up. It will also mean making bigger changes to the tunnel.

A couple of references:

A write up on the change over:

http://www.cuda-challenger.com/cc/index.php?topic=84774.0

Another reference:

https://www.youtube.com/watch?v=6Nz_ICxyMW8

most of this should apply to all cars that are being changed over from an A727/A904 to an A518


Another article, but may not apply completely unless you have a big block. The real point of interest is the pictures page down at the bottom. In the second row of pictures, first picture on the left, is a picture of an A518 (silver coloured) and an A727. Note how much thicker the A518 is near the tali shatt. This is why you will need a lowered trans cross member and nidufued trans tunnell its the actual physical size of the A518 case in front of the tail shaft. Link is here:

http://www.hotrod.com/how-to/transmission-drivetrain/43323-mopar-overdrive-transmission-swap/

You can also see the added length of the A518 (actually an A500, but same idea), which is what makes shortening up the drive shaft necessary.

The thicker part of the A518 case is where the 4th/overdrive gear is.