Swap Sohc to Dohc

My question is there is a guy around where i live willing to give me a dohc KA for free. Now this is just for the motor, what would be needed to swap into my 89 5spd 240 with the sohc. Can I use my sohc tranny on a dual cam?> He has a ecu, but no harness, the ka is from a s14 240, Also If i wanted to turbo with a s14 t28 and manifold what downpipe would i use,