I have been told the l series 120y one fits with not much modification and have bought one to try, just waiting for it to arrive, what stage is yours at datsandy again, I don't have a crossmember to trade mine has none :(
Or just go l20 be stroker with either z22 or z24 crank and run twin 45 or 48 mm Webers, should be good enough for between 150 to 200 hp that will be plenty in a 1200, that's what's going in my ute, I have the one being built for my 1600 at the moment :)