Rear end gear ratio

This is simple math what am I missing?
6500/7200 x 4.11=3.71s

But I gotta tell ya I think you TC is slipping pretty bad..
With a 29" tire, your Zeroslip rpm should be
(127 x 1056x 4.11)/ x 29 x 3.1416) = 6050
If the tach is trustworthy, your TC is slipping
7200/6050=19%
That, friend, I think you can take to the bank.
Thru the traps, a good TC might slip 8%? maybe less at your power level, Ima guessing. In any case 19% is huge. Imagine how fast you car will be with a tight TC and maybe 4.30s

With 4.30s the math says your rpm @127 should be 6330 at zero-slip, say 6840 at 8% slip..
But if you have enough power to go 133, then back to 4.11s and 133=6330 @zero slip, say 6840 at 8% slip
But if your cam is done early, these rpms might be out to lunch. I mean to carry the Revs to 6840 thru the traps still making power, is gonna take a wicked combo.
I'd be willing to bet a wooden nickle that your ET does not match your speed.