depends on the cars height... if its at or close to factory most headers wont cause problems. if its lowered some or you are using big tube performance headers like round port hooker super comp then there may be ground clearance issues.
the best quality/price "normal" pontiac headers are the hedman #28150, i have them on my 78 t/a that is about 1.5" lowere than stock & with 2.5 exhaust they have zero ground issues.
