Knock retard after replacing MAP. Why?

I replaced the MAP yesterday. I drove the car and on the way home i got knock retard for the first time ever. It never showed up on the 5 minutes of Datalog that included several WOT runs. It said 1 for a few minutes and then went away. Is this from the new MAP and why would it never do it with the old one? Is the Baro air pressure that the computer sees come from the map? It used to go up and down and now it stays the same.

The timing table is driven directly by the MAP sensor readings on the LT1. If your tune was designed based on the calibration of the old MAP sensor and it was off for some reason, and the new one is "correct" (or vice versa), you may need to fix up your timing tables.

How long before the computer would adjust for the new parts? I know the long term fuel corrections will need time to refigure since the old readings it got were wrong. I also unplugged the battery so all the saved data is gone.

The only thing "learned" are the long term fuel corrections. It won't "adjust" anything about the timing from the "new parts". It will just be looking up the timing using the correct MAP input. And it will now be using the correct BLM cells, based on the correct MAP readings. The BLM's in the Cells you run a lot will change in a matter of minutes. Some of the less frequently used Cells may take days.