Finally decided on a cam for teen SB. Should I bother with header?

I think your on the right track and a torque building cam
is a step in the right direction for sure if you don't run
any harder than that, but a good convertor will plant you solid in
the cams torque range instead of a slow drag to that range.
If you spent the money for a really good convertor, I wouldn't
be afraid of a 2600/2800.
And I would use new recommended springs/lifters no matter what
for a new cam.