I get questions all the time about how I mounted my engine. There are two options for this, you can buy pre-made plates from a source I won’t name or you can make your own. I chose to make my own.
First you need to pick up a set of cheap steel or aluminum Small Block Chevy to LS adapter plates. I picked mine up off of eBay for like $22 shipped. They did not come with hardware, which is fine as we will have to modify them anyway. Though be careful as some have the centers machined out and they will not work. You want just the basic plates like above.
Here you can see the two new bolt holes and studs I had to add, also you can see the four countersunk holes. This is required so the stock Dakota mounts will sit flat against the plates. The motor mount bolts on the LS engines are 10×1.50 thread pitch. You will need 3 countersunk 10×1.50 pitch bolts. Most hardware stores will have them. I picked mine up at Lowes for a few bucks.
The studs are simply 3/8×1.25″ Grade 8 bolts that I slid in from behind and welded the heads to the back of the plate to keep from spinning. The stock R/T mount has a cast in reinforcing rib on the back side of the mount. This normally fits between the bosses cast into the block, however since we are using flat swap plates, this interferes with the mount. I do not recommend grinding the ridge off completely as this serves a purpose of strengthening the mount. The rib is not parallel to the back surface of the mount. What I do is grind this rib level using a grinding stone on an angle grinder.
With the rib now parallel with the plate, I simply stack two 3/8″ washers behind the mount at each bolt location. This matches the rib’s thickness and supports the mount.
You will also see that on this side, I had to custom make all three mounting locations in order to make the mounts line the engine up properly. This required elongating on hole and drilling two new ones. The elongated hole will use a typical 10×1.50 bolt and not the countersunk type. Now, this is where you can screw up. I designed my mounts so as to move the engine down in the frame for more clearance. This meant I could no longer use the stock style truck pan as the front right corner of the sump was hitting the crossmember under the engine. You can move the mounting points around or keep them as I have and just run another pan.
The drivers side mount is a bit different, and does not require the shimming. However it does require drilling new mounting points. I could have used the stock upper hole on the rear of this mount, however the plates I used had a hole already drilled near the same point and would have interfered. So I opted to move the mounting point a bit lower. This does not effect the mounts strength at all. The lower rear bolt hole does not match the stock LS location, misses it by a little over an inch, however the boss cast into the block for that bolt location prevents you from simply drilling a hole next to it. So I moved the mounting hole back a bit, the cut the ear off the mount as not to interfere with the rear bolt.
In the photo above you can see that the drivers side mount uses the stock lower front mounting location. The upper bolt will require a countersunk bolt to allow the mount to lay flat. The hole in the top of the photo on the angled portion is unused.
You will also need to modify the stock frame mount on the drivers side to compensate for the added width of the mount plates. This comes out to about .500″. That’s it, pretty straightforward. I forgot I did have to slightly modify the notch on the passengers side frame mount by deepening it a bit to level the engine. This could be eliminated by adjusting the passengers side mounting locations up a bit.