not sure of the head changeover date. I just ordered the recessed valve head as that's what was fitted to mine. All manifolds[inlet/exhaust] just married up no problems. In fact I've now fitted an intercooler off the mkII model with manifold and that all bolted up just fine. Yes mine is turbocharged. Headbolts, well they recommend you change them, but I don't think the 2.3/2.5 bolts are stretch. I reused mine, just retorqued them after 500 miles, as said no problems after 6 months encountered so far. Hope this helps <img src="/forums/images/graemlins/cheers.gif" alt="" /> ps my motor is in a Mitsubishi Pajero, hence the mkII comment. Also, gaskets available at rockauto.com based in the US but ship worldwide {I used to own an 88 GrandAm so used these people for the parts}