The 068 is what I like along with heads that will give you around 9:1 compression. If this is a street car, don't fall for the big cam high compression deal. It will shake, stall, stink and suck gas.. Keep it stockish. I liked the Nunzi 2041 cam
http://ronspontiacpage.com/reference-pages/nunzi.htm
Have the exhaust heat ports filled and keep the compression in the 9s.
I have a 1978 truck 454 in my 69 el Camino, th400, 2:87 its low compression but it goes and I never had more fun with a car.
There's a Pontiac web site that has all the head numbers and descriptions. I think it was called Wallace or Rons Pontiac page.. Pontiac made a lot of real cool heads for that motor so your in luck..
The Summit 2801 is also an excellent cam for a 9:1 compression 400..