Firstly, there is a search function at the top off the page in the tabs under the rollaclub banner, when you figure out how to use it it's great. This question is so redundant it's not even funny.
Okay so basically the engine is an A series engine, therefor you need the parts out of an A series car to go with it, ie AE71, AE86 blah blah. I've never done the conversion myself, but I've read about it a fair bit, From what i can recall you need:
- AE71 crossmember (bolts straight in apparently)
- AE71 Pedal box (for hydro clutch)
- RWD manifolds (or cut n shut, unless you can get your hands on a 4AGE already set up for RWD)
- T50 gearbox (came in AE71, AE86, T18 from what I know, not sure if this bolts up to your K series gearbox crossmember)
- Custom tailshaft to fit your standard diff, or do a diff swap
I can't even remember, those would just be the main things there would be so many other small things to sort out like suspension and brake upgrade to pass engineering and so on, just read this: http://www.rollaclub.com/board/index.php?showtopic=5644