I just bought a 85 CRX DX which is very clean. My 90 CRX SI is getting a brand new B18C1 and would like to rip it's motor out and put it in my new 85 CRX. Would it just drop in and bolt in or would I have to get any extra things to make it work?

 

No, it's not a direct bolt-in... I think it's the drivers side mount that is the main problem.

You would also need to figure out how to carburate it or convert the car to fuel injection.