The 1970 heads were again changed from 1969, using slightly lower compression. The 1970 base 400's used the 067 cam regardless of trans, and the 1970 RAIII's received the 068 cam regardless of trans.
Now how about these WILD Pontiac 067 cam specs for the GTO.
A whopping .406 lift int/exh (break out the lifter bore braces guys)
A staggering 273/289 adv. duration.
It's amazing that base GTO's ran as well as they did. That earlier cam we mentioned (known as the 744) that was used in early RAIII 1969 GTO's was also used (with a different distributor gear) in the 73/74 SD-455's. Still nothing to write home about. Again, .406 lift, but a little longer duration at 301/313.
Pontiac utilized low lift flow to fill the cylinders in order to make power across a broad rpm range. That's why most Pontiacs were all done by 5200 rpm.