ok,

350 gm mercruiser.

I had a burnt valve. I took the head in to the machine shop and had it
replaced. I put it back together, did the timing ect. It is running a lot
better, but doesn't seem to have the full power. On the engine it says that
the max rpm should be 4400 - 4800. Although I only seem to be getting 4200
at the most. Also it seems a little slugish out of the hole. I checked the
compression on all clyinders and they are all very good. (160-170). I feel
as though it might have something to do with the timing. I read in a book
that the timing mark should hit in the same spot everytime. It's pretty
close but seems to very about 2-3 degrees each time. Might this be the
issue?

Any thoughts on what the problem might be here?