5.3L Chevy Motor Swap – Motor Placement

Note: this page may take quite a while to load all of the images, please let it load so you can see all that I’ve had to deal with in this section, because this is one of the most important parts of this project!

Once I got some time, I knew this job was going to be one of the more critical and difficult jobs with this project…but it has also become one of the more rewarding jobs, so if you tackle this project yourself, take your TIME with this part, because it is extremely important to do things right the first time!

The very first thing I did was get my grinder wheel and clear the areas on the frame where I figured the new motor mounts would need to be welded:



The next thing I did was simply hoist the motor with the cherry picker and slide it into the frame rails to see “overall” where we were at and what modifications and adjustments were going to be necessary to actually get this thing mounted.


I bought advanced adapters motor mounts for the GEN III Chevy Motor… and essentially bolted it on to see where things would line up….more on this in a minute.   I got to thinking, how I was going to actually deal with the transmission and transfercase.  This is where it gets interesting….

KNOWING in advance that I was going to have to shift the motor over to the drivers side by at LEAST 1 inch, maybe 2… because if I didn’t do that, the front driveshaft would never be able to fit.  See, I’m using the Dana 300 transfer case with a 4L60e transmission, and those transmissions have very large pans, and the pans stick out toward the passenger side, and CJ’s happen to have a passenger drop front axle, so that means things are going to be very tight with the front driveshaft clearance to the transmission pan.  I test fitted the transfercase to the transmission before putting the motor assembly in the Jeep just to see if it was going to work AT ALL… and MAN is it a close fit, when I first looked at it, I didn’t think it was going to work at all but after actually bolting the driveshaft to the transfercase, I was able to see just how close it actually is.   Look at these to see what I mean:





You can see that the flange (lip) on the transmission pan is definitely in the way, so I shaved it a little on the back side… then after getting the motor in the jeep, I ended up shaving the whole passengers side lip all the way off, just to give it another 1/4″ of room… it’s a really tight fit, but it will be ok.

The next thing I did was put the grill/radiator/fan assembly on to make sure I would have enough clearance from the motor where I had placed it… looked good to me!


With the motor approximately where I wanted it… I decided to try to utilize the original motor mount frame holes (original mounts on this CJ were bolted in) in line with one or both of the holes in the frame side mount from advanced adapters. I ended up using the middle top frame hole matched to the top hole of the AA frame mount, ran a Grade 8 bolt through it and let it sit there until I could get my brother in law to come over and weld these mounts to the frame for me…since my welder wasn’t powerful enough for this task.


On the passengers side, I ran into an issue…. the frame was a little too wide, so I had a half inch of space to make up for with the mount on that side…


easy enough, I went to the local steel supply and had them cut me a 1/2″ thick plate and then cut a couple of holes in a template that I scribed out for them.. voila…



Now it was time for my brother in law to come weld this puppy in… We measured probably 5-6 times before we ended up with this setup…






Once they’re welded in, take a wire wheel brush on a drill, and go at em to clean em up, and get rid of the burrs…then paint them with some rust inhibiting paint… done!



After it was all said and done, and the motor mounts were welded in, and I bolted it up to the mounts with the offset, it is about 1-3/4″ shifted to the drivers side, check out this image to see just what I mean:


Here is a list of points to measure to make SURE you have enough room for motor movement (very little, but there will be some) and driveshaft clearance (in no particular order):

  • motor shift to drivers side, by at least 1-2 inches for front driveshaft clearance of transmission pan
  • motor to firewall clearance, so you have room for any connections that go back there, like vacuum, electronics and fuel delivery
  • clearance from front of motor to the fan/radiator setup you’ll be using
  • clearance from the top of the motor to the hood, you want to make sure you’re not too high so you can actually close the hood!

On to the driveshafts…