I got a b16 that I just blew the crank on. I've got a b18b crank laying around, wondering if it will fit and if it will change my compression. also can I use stock b16 rods and pistons. thank you.

 

if you use ur ls crank youll need ls rods and if you use that set up youll need custome pistons if not the pistons will stick out of the block.

 

B18B rotating assembly parts won't work because of the difference in deck height between the B18s and B16As. As stated above, the pistons would be higher than the deck if you tried to use them in a B16A block. Your best bet would be to find another B16A crank or block, or to find a B18A/B block(they're a dime a dozen) and put your B16A head on it.