Yeh i was researching on d series and stumbled somewhere the IMs are the same. And the d16y4 had a lower final drive. Guess ill just stick with i/h/e and a cam regrind while i change my timing belt, needs replacing pretty soon. Anything pretty cheap to do while the rocker cover is off? I heard the valve springs but the d16y4 are pretty strong. I'll be doing a tappet adjustment to match the cam.