supporting engine for k member swap?
Another option is a cherry picker connected to a chain going into the front of the driver side head and back of the passenger head. Of course, then you have the cherry picker in the way.
I would suggest you leave the stock manifolds in place so you can do the K-Frame swap like this. After you've installed the new K-Frame, your new headers will slip in pretty easily. Cinch up the straps a bunch but you're not trying to lift the engine. When undoing the motor mounts and droping the frame, the enigne ain't going anywhere. You are dropping the oil pan to have a look around, right?

I took some unistrut and laid it across the shock towers. Then a strap from each exhaust manifold to the strut. Drop the K-frame and the engine stays put.






