Ryan, it's not as bad as Paul makes it out to be...LOL!
He has done a lot of custom work like making his own LS engine accessory brackets, etc. Most all the parts to make it go together are available. Mine is custom from top to bottom, so it's been a lot of work.
One thing you might want to think about if you plan to upgrade to an LS engine is the fuel system because you will need an in-tank pump and dual fuel lines for EFI. We can talk about that if you'd like...I have a solution for that. Also plan your exhaust out for the swap, as well as a plan for engine cooling (LS hoses both come out on passenger side).
As in any project like this, you will have to deal with the steering column and shaft, brake lines/booster/master cylinder, fuel lines, exhaust, driveshaft, e-brake, and a few other things. We already talked about most of those.
Paul, any other words of advice or areas to consider?
It should be an awesome car when finished.