along with what they said the compresion ratio is alot different, an LS is 9.2/1 and a b18c is i think 10 or 11/1 there is a thread on here that will tell you the different specs on each engine (and car as a whole) like LS, RS, GSR, T-R.......in my opinion there is a huge difference between the two both with its own advantages. But with a build, the motor you have, you can put a V-tec kit on there which is kinda expensive but very nice for the power you would get out of it......or you can always go the boost route, and with an LS block and the low compresion that it has you can boost roughly 8-9lbs and still be safe with it, but you still would have to upgrade a couple things.....kinda went of course but those are you options if you were looking at what you could do with you motor, hope that helped a little bit.