TCC locking up at 74MPH at W.O.T

[Kitch]

I don't know how I missed it before!

Part of the problem I've been trying to get rid of ever since I upgraded the motor to Vortec heads is counts knock under W.O.T. (Wideband AFR's 12.5-1) and now knock counts when I lift off. I could get about 200 KC's in a W.O.T. test run from 30-70 MPH and another 900 KC's if I reached 74 MPH and the TCC locked.
I would get noticeable a knock count increase when the TCC would lock and drag the RPM back down under load.

Interesting, just looked at the last log I had with the TCC not locking and it I still got about 800 KC's in 3rd gear at 3400RPM @ W.O.T. with 27.8º timing.