Torque Converter? Where am I at? What is compromised?

AJ/FormS said
With 3.91s, 28.2s , a TF automatic, and the GVod, the mathy is
(70 x1056 x3.91 x .78) divided by
( 28.2 x 3.1416)=2545rpm
If your tach is accurate then (2700/2545) =1.061 so 6.1% slip; seems a lil excessive for a Scamp. More typical is 2/3%

Currently the tires are 255s. So 27.3 when new going to be 28.2 with the next set of tires. My math got me 2.7% thanks. Closer to norm?