There is a little thinking before it will work, I have a LS1 and right now I'm in the middle of figuring out all the mods to make it work. Motor mounts ( custom fab -DONE- ) I had to take the oil pan off to fit the motor mounts. Now I'm debating weather to mod the pan or mod the frame. Most likely going to mod the pan. Question I have for you now is what trans are you backing the LS1 with ??? I have a 6sp behind mine and have had to make a new trans mount. I have already placed my LS1 in and had it sitting perfect now it's just a matter of the oil pan. I haven't got to the driveshaft yet or the hydraulic clutch mods. The wiring is actually the easiest thing in this whole swap, I bought the full painless front to back wiring kit with the LS1 wiring add on kit as well. Good luck and if you do decide to follow through with it, it will be well worth it in the long run. If I were to do the swap again it would have an auto trans, alot easier to figure out the gear shift.
Id like to see pictures of the wagon. My 60 Impala 4 door has an LS1 in it with a 4L60E from a 2002 Camaro. No modifications had to be made to the oil pan or frame. Custom motor mounts, high pressure inline fuel pump, and wire harness fabrication and it runs good! Im waiting on brakes that should be here next week to help it stop a little!