2000 C2500 Sprocket Marks

2000 C2500 350 Vortec.

In the manual that I have, it says that when installing the cam sprocket, the mark on the crank should be at 12 o'clock and the mark on the cam sprocket should be at 12 o'clock also. I have also noticed on the internet that the mark on the crank should be at 12 o'clock and the cam sprocket should be at 6 o'clock.... Which is correct? Thanks

The vehicle is a 2000 GMC. Old body style.

They are actually both correct. With the cam @ 6:00 it's easier to get the marks lined up correctly. However in this position #1 piston is at TDC on the exhaust stroke and #6 piston is at TDC on the compression stroke. Rotating the crank one full turn will put the cam @ 12:00 and #1 piston at TDC on the compression stroke which is were it needs to be to set the distributor correctly.

Hope this helps.

Wow. Duh. That makes sense. Maybe i should have thought that one through before posting. Thanks.