I've got a 90 integra ls sitting around here for parts and i was wondering if i would be able to use it to do the rear disc conversion, and if so, what parts would i need off of it?

 

well you dont know how to search or didnt search hard enough.. type in rear disc conversion .. archived content obviously .. pick 92-00 civic/del sol forum .. i recieved 172 results .. there is tons of info on this

https://honda-tech.com/zerothread?id=641639

https://honda-tech.com/zerothread?id=642479
scroll down to suspension/brakes

Search its all there believe me

 

I found this a while back, havent gotten around to trying it yet, but it looks reasonable.
DIYNetwork Disc Brake Conversion

Hope it helps

 

Appologies, the donor Integra there was a 97. I dont know if it will swap directly with the '90