The guy on you tube has some goofy stuff going on. It might work but it sure ain't pretty!
Are you using a v belt setup like the original engine or are you using a serpentine drive system?
original V belt = standard rotation pump, bypass built into pump/block/head
Vortec serp belt = reverse rotation pump, external bypass using hose.
Vortec blocks do not have the bypass hole drilled into the block. The bypass is a hose on top of the water pump & goes into the intake. (see pic)
If you run a stock GM serp belt system, run a vortec pump with a bypass hose & your done.
If you run a V belt system you will need to drill the extra hole in your block for the water pump AND DRILL THE HOLE ON THE DECK OF THE BLOCK & THE CORESPONDING HOLE IN THE CYLINDER HEAD & MAKE SURE THE HEAD GASKET HAS A HOLE THERE ALSO.
If you google SBC water pump & SBC Vortec water pump you will see pics that show the vortec pump has one less hole.
Read this link, Captainfab has some great info & pics:
http://67-72chevytrucks.com/vboard/s...d.php?t=610112