Hi ya mate..

As far as i know the 2wd head as a two bolted thermostat and yeah 4x4 as a 3 bolted one.. i dont think there much differents apart from that as i had a f reg 2wd saff with a 4x4 200 block runing a 2wd head , a 4x4 exhaust mainifold and turbo which i belive gave more bhp...