The car looks like it is performing as it should.If that is your E.T, with mufflers,its actually decent.
what I would check,or look to improve:
Do you get enough fuel at the end of a 1/4 mile race?
I believe a victor junior and 850 D.P. would add another 3-4 M.P.H.
If the manifold/carb/fuel delivery added 5 m.p.h. then,,,I would use the hooker 1 3/4 primary pipe headers.
if that helped,then I would change cams after looking what helped the most