I'm planning on doing an ls/vtec and was just wondering does it matter if the oil pump is obd1 or obd2?

 

If you have an OBD2 car, you need the OBD2 pump for the mounting place it has for the crank fluctiation sensor, otherwise it doesn't matter. I think the timing belt covers will fit funny if it's the "wrong" OBD oil pump, but thats it.