My car already has the smog pump removed, and I'd like to remove the air lines if possible. All they do now is get in the way when trying to change spark plugs. I know some people have had mixed success by just unbolting them and putting in threaded plugs, but mine don't want to budge. I'm sure I'd just round off the fittings. Has anyone tried cutting the tubes off flush with the fittings, and welding them shut?

If you think you are going to round them off, just cut the tubes off of the fittings then use a 6-point socket. Don't use a cheap socket. I broke a Craftsman socket removing mine.

if you use a air hammer with the chisel bit a just zap them it will cut the pipe and pinch it closed in one shot. I do this all the time with amateur dirt track cars.

Or you could wake up in the morning and spray all of them with penetrating oil, then come back in and eat breakfast. When your done eating breakfast, read a newspaper/magazine for a little bit and then go spray them again. Come back in and do some other chores, and after another hour, go back and do it again, and again, and again... I did it maybe 3 or 4 times and then used a tubing wrench and they all came right off. No rounding or cutting required.

Thanks guys, I may just try to unscrew them the 6-point socket idea is good, I didn't think of that. I'll also try the penetrating oil, i've seen that stuff work miracles before. I'd prefer not to cut them and pinch them off though, someone did that on my old 83, and i can't even remember how many times I cut myself on those things.