first off, the b18a1 IS an LS engine. It's also the GS engine, they are one and the same. The LS engine is not vtec. The b18c and b16* are vtec engines. You could potentially take the head from a b18c, b16(anything from the same generation motor, which would be b16a series), or the rare b17 engines. This will be a very difficult swap for you to do, because (correct me if I'm wrong) you have a hydraulic transmission in the car now, and the b18a1 is a cable transmission. Try to find an engine of the same obd so you don't have to rewire everything too. going obd2 ---> obd0 isn't necessarily a good idea.