Donny...I see you are not getting a whole lot of responses. Headers on Pontiacs can be a sticky wicket and rarely painless due to their down-turned exhaust ports on '81 and earlier V-8s. The closest thing to "painless" headers were the now long gone H-O Racing's Tri-Y versions. They were fantastic. I haven't used any type of tube header since those. As you already know, I use the R.A.R.E oversized cast iron round-port manifolds. Doug's Headers get good reviews from folks if you do a search. Below is a nice video of a fellow installing Hookers on a '71 Formula you might gain some insight from. Depending upon the manufacturer and style you may need to install an oil filter adapter to reposition the filter for clearance. Maybe a brave person who has done this successfully will chime and help you with up close and personal experience. PS: You might also want to consider a compact high torque mini-starter for more clearance.
Pontiac Firebird Hooker Headers #4901 for Pontiac engines. Complete install - Bing video
Pontiac Firebird Hooker Headers #4901 for Pontiac engines. Complete install - Bing video
