Seems a little bit low, but when I baselined my I made a little higher #'s than you (my engine only had 43k though). I would have thought you would be higher for having a 70 mm TB and Cobra Intake but I can see your stang pulled higher in the higher rpms compared to mine.
Mods at the time were:
Longtube headers
2-1/4" Catback and H-Pipe
BBK Pulleys
Stock Speed Density
Just curious what type of dyno did you use?
Oh and I did built a new engine and let me tell its a world of difference! What HCI are you planning?