I'd really like to know what intake you took off......I'd guess a Performer or similar?

What I see is you went 2 different directions with the car......

Single plane intake on an engine that probably makes peak power at 5300 RPM.
Cam is bigger, probably not detrimental to the combination but, not degreeing
it in is a BIG no no.
Then you went from 3.91 to a 3.55 gear........2 directions this case.
I would attribute .5 second to not spending time tuning at the track.

I'm not going to bust you up but, you changed the engine to move the power
up in RPM and the rear end to lower it.

That's just what I'm seeing.