Ok I thought I knew what I was doing, and have read all the threads that come up in searches, but I'm still confused.

I'm doing a 3.9L to 5.9L magnum swap in my 90 vert. The 3.9L had the 4412141 adapter plates and the urethane barrel motor mounts. I thought the 5.2/5.9 was simply the 3.9L extended. The motor mount spots on the 5.9L measure the same distance to the back of the motor as the 3.9L so the extra distance is pushed forward as we all know (reason for pusher fans).

However, these 4412141 adapter plates in no way line up with the mounting holes on the 5.9L. So what do I need that will mount to the 5.9L block and allow me to use the 3.9L urethane barrel mounts?

 

Here's a picture of the adapter...

http://www.justparts.com/Auto_Parts/Engine-Mount-Bracket-3-9-Liter-88-Dodge-Dakota-4638577-4412141/24714292

I'm really confused now because that part seems to be only for an 88 dak. And I can't find my type of mounts anywhere on line.

 

That IS confusing.

Is your truck 2WD or 4WD?

Because ALL the 5.2/5.9 L Magnums bolt up like ALL the 3.9 motors, LA or Magnum, on the block.

And those don't look ANYTHING like the motor mounts on my 1988 2WD ...

RwP

 

2WD

Here's a pic of it on the old 3.9 block before I removed them...you can see that adapter plate under the bushing mount....But I can't find anything like this online

That upper bracket headed to the left is a transmission bracket...haven't seen that arrangement either.

 

pic of it unmounted and cleaned up/painted

 

Pic of a number on the bushing...4412140 which shows up as a Dodge motor mount, but not the same pictures when I search it






Example on search: http://www.ebay.com/itm/Engine-Motor...-/261523192603

 

FYI, my 1990 service manual shows the exact above.

Here are two pictures

The 3.9L mounting holes are shown in a triangle (yes the pic is an inline 4 block, but it's the same mounting hole configuration on the 3.9L)

The 5.9L mounting holes I thought I could use in an upside down triangle

Problem is the vertices of the triangle are longer (holes further apart) on the 5.9L than on the 3.9L. The distance from the center of the mount to the tail end are the same.

 

So, I think I figured it out!

After looking more closely at the adapter, it has two interlocking triangles! One set is tapped and the other set is through hole. So as it turns out, if you orient it correctly, the through holes line up with the magnum mounts, and the tapped holes line up with the motor mount.

 

Heh.

That makes sense.

RwP