Here's some info that may help, but not specific to the Q motor.
http://www.network54.com/Forum/424840/message/1123103583
I am presently running big blocks, but I had marine small block motors in the past and I don't recall seeing any timing marks on the front pulley, like you would normally expect. I think the timing marks were on the flywheel, just like they are on the big blocks, visible though a port. You probably time to that mark at 500 RPM under load. It will look like a drill mark or a hash mark. No degree marks.
The Q motor is just the same as the 327, except for a little different intake manifold. I would suspect it would take the exact same timing. Since I think Mark has recently done this on his boat, he'll be able to tell you for sure.
Assuming it's the timing as you say, but there are other factors that will keep a motor from reaching top speeds, and propeller size is one idea that immediately comes to mind. Overpropping a boat is tough on a motor, and it will never feel like it has the power it should under that condition.
Good luck with your project, Howard