Chui, I feel your pain bro. I was in your shoes a couple years ago when I decided to LS my 66 Skylark. The Buick guys were borderline hostile. Since Pontiac used LS in several cars, I am surprised to see the same sentiment here.
The best approach is to read through threads on the Chevy cousin conversions since a lot of that will work on your car.
You're going to need engine stands and adapters, pick a tranny, upgrade your fuel system, figure out what you're going to replace your gauges with, get a new radiator, change your driveshaft, maybe a different oil pan and accessory drive, and get a wiring harness and a pcm tuner. Other than that, piece of cake.
Take it a step at a time beginning with getting the engine/trans combo to fit in your car. Depending on your trans selection, you may be looking at modifying your tunnel to get it to fit.
What are you putting this in?