Headers?

I think HR magazine did a comparo and found over 40hp after bolting on long-tubes; with no tuning changes; hinting at more power lurking. I think they used the 284 Magnum cam. That is sortof like 2 cam sizes or dieting over 400 pounds out of your car.
Are long-tube headers worth it? Hunt up the article, and choose for yourself.
The more overlap your cam has, the greater will be the power difference.
Myself, for a performance combo, I would do whatever I had to, to get long-tubes on. Even smogger 318s like long-tube headers.
But shorties still provide a place for the hot, high-pressure gasses, to go when they burst out of the chamber, and at least some distance to get straightened out before they hit the head-pipes; and so the engine doesn't have to work quite as hard to push the exhaust out. That's gotta be worth something.