The notched heads were supposedly on the 99-01 models. I have a 99 5.3 and 00 4.8 and both had notched 706s. Graphite gaskets are the trick!

 

All I know is I put a set of notch heads on a motor with MLS gaskets once. That's the day I learned the MLS do not work with the notch heasd. It pissed coolant everywhere when it hit the dyno.

I'd get away from the notch heads so you don't have to worry about it.