What does it weigh again?

Is it dead hooking now?

For a comparison on the stall speed, with a 448 running 260cfm 906's and a torker II intake/850, 259@.050 cam, I ran 5300 stall with 4.56's and 29.5 tires.

Your heads and manifold are much bigger, along with a longer duration cam.
It's a "street" car so I know you'd like to maintain some degree of streetability, but if getting the best ET out of it was the goal, I'd want another 500 flash out of it.

As for a cam swap, there is probably a little room for improvement there as well, but I don't think it would be anywhere near 3-4 tenths, and without more stall I feel how much different you could go is limited.

What I would try if I were going to do a cam swap is a Comp MM lobe, 271/271-108, in at 104.
Install new springs with the swap....... Extreme care during break in.

However, if it's in the budget....... Just put a roller in it.