Header life is reduced but I wouldn't take it off if it's working. It's not going to hurt your engine. Headers are kind of a consumable anyhow. Make sure your timing is right and dwell is proper, then check where your vacuum advance is hooked up and possibly switch it. Check for vacuum leaks. The headers on my V8 S-10 have been wrapped where they are close to the clutch master cylinder since 1999 and haven't rusted out yet.
