[fredmeister]

Thanks guys but I am already committed to the SC cams as I have been running them for 4000 miles now with the engine before needing this top end rebuild (long story). I dont want to sell them or buy another set of 964 cams but just want to know what I can do to the timing when I rebuild the top end now.

Tippy, your engine sounds similar to mine except for the Carrera intake and heads. But with my ported turbo intakes our heads should flow similar. I had my cams timed to 1.51mm previously (shooting for nominal=1.55mm) and I did not notice any perceptible drop off around 6200-6400rpm, though I did not wind it much more than 6200rpm unless on the occasional long straight. I wonder what turbocharger you are running and if that has a very large effect on you losing power before 6400rpm. I am running a k27S with zork tube exhaust. Had the boost limited to 0.8-0.85bar on the mechanical VDO gage.

If I retard the timing much more beyond the nominal 1.51mm previous, say around 1.42mm which is at the lower timing limit, I wonder how much effect it will have on raising my power curve into the upper rpms. I dont want to risk valve to piston contact either in searching this out.
Anyone else go down this road before that could chime in?

Thanks for the input so far Tippy and JFairman.

Fredmeister