ZC = 1.6L Non Vtec DOHC D series engine. Cheap, Ok power.
B16a = DOHC Vtec 1.6L B series, more expensive, great hp, not much torque.
b18a = DOHC Non-Vtec 1.8L B series, less than B16a, more than ZC, great torque, great 4 turbo, not much go after 3rd gear.
b18c1= great allround engine, requires a lil more work, great HP and torque, most expensive.
These are 90% of the engines u will see put in ur car, if u need anymore info on which engine is best, u gotta give us a detailed list of ur car, money, what u wanna do with car, full race, semi race, weekend only, autoX, and experience for us to tell u what to get.