Haven't done much with this project but I did spend last weekend helping a friend fabricate an Doubler crossmember and exhaust after he swapped in a 6.0L, TH400, and Doubler in his K5.
If you look at the front mount under the factory adapter, we had to cut down the round bushing to fit the rectangle tube. We forgot to cut down the washer to match so we just threw in the rectangle washer from the factory mounts. That bushing is there so support the transmission so he could remove the Doubler without needing a jack under the transmission.
You will notice there isn't a front shaft so we used a 2x4 to make sure there was clearance with the exhaust to allow for one.
One of these days I will invest in a plasma cutter, but in the meantime, I had to torch out the holes for the bushings in the crossmember.
The exhaust comes into a dual inlet, single outlet muffler. That was more difficult than I planned as evidenced by all the pieces of pipe.
For the time being the exhaust dumps in front of the rear axle. He's going to put 56" springs in to move the axle back 4" which will change the shocks as well. We figure it would be better to do the tailpipe after all those changes are made.
Oh and you will note the temporary rear shaft we made. It's from the intermediate section of a 2pc shaft that was in the 95 K3500 donor for my 4l80e. We just cut the tube and welded it back together at the appropriate length. You can see the support bearing still on the shaft with the rubber isolator removed. This will make it easier to move the truck around. Knowing Nate, it wouldn't entirely surprise me if it shows up to the first trail run with that shaft still in there....
