how to install headers?
I put my Jegs headers in the normal way the first time, and then again a 2nd time the assembly way pictured above, when I did my 360 swap. It was so easy the assembly way it made me think it would have been faster the first time to do it that way even if not completely removing the motor. Instead of jacking the motor up (which doesn't give you much more room anyway), dropping it down seems easier. Pull torsion bars, pop the upper ball joint, pull gas line, pop off upper and lower radiator hoses, disconnect some wiring and the front brake lines at the frame, pull the top bolt on the shocks, pull the roll pin on the steering coupler, pull the main bolts in the trans mount but you should be able to let the driveshaft just stay in place. Jack the front end way up and put it on jack stands. Then use an engine hoist and hold the assembly up while pulling the K frame bolts. Then lower it all down to the floor, install headers and pull it all back up with the hoist.
Then again, after typing all that out it doesn't seem easier anymore and I'm sure I left out a few parts! I had all that stuff off anyway but was really glad I put the headers on before installing the motor, and really glad I did it from the bottom. I had taken it out from the top and that was a mistake as well.
Don't worry about it too much, I bet hundreds of thousands of these crappy headers have been put on a bodies since they came out, you'll be in good company LOL!