Before we started hacking, we needed to secure our K-frame from any distortion. Experienced fabricators know how prone metal is to shrink, twist, and distort when large amounts of heat is applied. To keep our engine cradle from twisting out of shape, we tacked on a makeshift jig or frame to keep our K-frame still looking like its namesake letter. | 
Our first piece was the center plate. After a series of spot-welds to make sure we were aligned right, we ran fillet beads both inside and outside. Though the K-frame wouldn't be absorbing any sort of torsion like it would have if we had retained the motor mounts, we still wanted to make sure that it was solid and rigid. | 
Welding is only a portion of the fabrication process. Our handy Milwaukee hand grinder and a couple cutting wheels proved its worth during this project. We continued by cutting out a pair of 4-1/2- x 2-1/2-inch plates that would serve as our side box plates from our 12-gauge sheetmetal. |
Using a Miller MIG welder, we were able to quickly box in our K-frame. We tried to keep our welds even, uniform, and in a tight overlapping pattern. "Fillet" welding means welding two aligned, beveled edges together with a gap placed up to each other apart by only a hair. This allows the new weld to penetrate all the way out the other side. This ensures when you grind it smooth it's totally welded. | 
We completed one side to illustrate how we covered the factory gap in the bottom of the K-member. We chose to slightly blend the welds since we knew that our Charger was going to be a street-legal race car, meaning we were going to be spending lots of future hours underneath this car. We didn't want anything sticking out that would snag us. | 
Flipping our cardboard stencil over, we used it to make a mirrored twin of our first side. We tried to over-secure our boxing job because we didn't want any cracks or breaks to occur. |
With the top half of our patch attached, we cooled the metal down with a couple quick shots of water. We didn't mind overlapping the beads because we knew we would be going over the welds with the grinder later. | 
Using C-clamps to close the larger gaps, the rest of the patch was buttoned up. The slight spaces between the patch and the K-member allowed for full penetration of the weld in the material. | 
Compared to the finished side, it is evident we have a lot of blending and smoothing ahead of us. Using different grit grinding wheels, a flap disc, and a wire cup wheel, the patch plates were flowed into the K-member. We made sure to not grind the welds cleanly off as many over-enthusiastic grinders tend to do. |
Using the cutting wheel and the more aggressive grinding wheel, we "scarfed" off the rest of the remnants of the engine mounts. The jig was also removed since the majority of our fabrication was completed. From this view, it's clearly evident how much room our modification made for a larger race oil pan. | 
Finishing off with a flap disc and wire wheel, the rest of our blending efforts went smoothly. Factory K-members aren't very pretty from the get-go, so we weren't terribly interested in making this project a show-worthy effort. it was going in a race car after all. | 
For an extra measure, we pulled out the tools again and cut inch-deep slits, four on our main brace, top and bottom, and two on each side, likewise. We fill-welded them to make a type of cross brace in the plates. Sure it's extra work, but once again, we wanted to guarantee our work would stay together. |
With a can of semigloss black paint we sprayed over our work, trying to go for a factory-style, subdued look. this, like most everything else, can be powdercoated, chromed, or professionally painted. All we used was a high-durability engine enamel to protect against scuffs and scratches that are sure to come. | 
In addition to cutting and boxing the K-member, we also fill-welded the gaps around the steering box perch and along the seams. Though the factory K-frame stays together well and we won't be mating an engine to this, we wanted to ensure total structural integrity. | 
Finally finished, here the newly opened and boxed K-frame is ready to be installed. We loosely fit the engine cradle, letting it hang on its bolts before tightening them up. We wanted to make sure the K-member had not distorted during the fabrication process, so we slowly tightened the K-frame to the subframe. Thankfully, our jig proved the trick to keeping our piece from twisting and it fit perfectly. |