i just got back from florida with my brother in law. he picked up a 90 civic hatch for very cheap. so it needs a clutch no big deal. my question is the block says d15b1, and the head says 16valve. now from what i researched so far a 16 valve head is off of a dx motor and a d15b1 is from a std and is only 8 valve. now it could be that its a whole d15b1 engine with a dx valve cover, i haven't had a chance to take the valve cover off to see. would a dx cover fit on a std head? also the guy who had it before him had a 50 shot of nitrous running on the stock motor. would the stock pistons even be able to take that? its late and im tired but if anything doesnt make sense im sorry. anyone have a clue?