If I were to put a b20 in my 90 crx, couldn't i use jdm crx b16 motor mounts?

 

B20 = 2.0L LS motor, thus the same physical size and everything bolts to it the same. With any B-series motor into an EF chassis, you need a mount kit or to re-weld the frame brackets. If the B16A motor has a mount kit, then you can transfer that over to the B20, but you'll also need to transfer the driver side engine bracket from the B16A motor to the B20 motor in order to get the correct fitment with the driver side mount.