If you're not going to rev over 4600 to 4800rpms you will be fine with any brand of standard valve springs. Pontiac used factory valve springs as rev limiters to reduce warranty issues. I have a set of Erson springs that made good power to 4800 on a dyno before they started to float. They only have about 1000 miles on them. I'd let them go cheap if you're interested. I wanted some that would hold up to 6000rpms so I changed them out.