Bob,

The spec sheet recommends no more than 32 degrees. Not that that's set in stone. He may have installed a cam that allows a little more lead. You can fiddle with the timing a few degrees each way and see what happens. Keep away from any ping. These Vortec engines don't need a lot of timing lead.

I don't worry about initial timing any more. I spin the motor up until the timing stops advancing, then lock it in at the recommended setting. Whatever it drops back to on idle is what it is.