all motors from before 83 (except the 83 prelude) are interchangeable. a popular option (that i am doing) is to use the EK1 motor from the 80-83 accord or 80-82 prelude. it's 1.8L and comes stock with more power than the old 1200 and 1500's. if you have a 1200cc you can use the crank and rods from the 1300's (80-83 civic) to turn it into a stroker or just swap in the 1300. you should have a look at
http://www.civic1200.com/discus/ for more (and better) info.