Nope, let me clarify a couple things.
Most B20's use either the PR4 or P75 head, which are the heads that came on B18B1's and B18A1's. The P8R head with oversized intake valves only appeared on Orthias, which were a CRV model from another country.
Having said that, if the stamp on your head says "P75" or "PR4," you use everything from a Non-VTEC motor in terms of cams, valves, springs, and retainers. If you have a "P8R" head, you still use a any non-VEC Cams, springs and retainers, but you will need custom intake valves made if you want to upgrade.
For the bottom end, if the stroke is the same as the B18B1 and B18A1 motors, then the rods are the same length, and therefore all non-VTEC B18 rods can be used. The pistons are 84mm stock, and can be bored to a maximum of 84.5mm (Maybe 85mm, not completely positive).