OK...I am wiring my car all for a b20 obd1 so its ready for a b16 head when I come up with the cash after I get my full-race bar and radiator. Been looking for a header for the crx with the b swap and cant really find the answer I am looking for...Do I need 2 o2 sensors or just one and a 1wire or 4wire????

 

Are you running OBD-I with an LS ecu?

Only first gen B16's had that ghey dual 02 setup. OBD-I requires a 4 wire 02 sensor.

 

I be using a p28 ecu that I got for free and I have a b20 about to install in my car with a p75-8 head...I like to only use one o2 so what ever head requires that from a b16 i go with that...not here to post noob questions but new to having a b in my ef

 

obd1 use the 4 wire o2 sensor, obd0 use 2 , one wired o2's