Hmm. I relooked at this recently as it was discussed on a FB forum. The following may make some sense:-)

I stuggled to work out which way round to look at the timing calculation, You can calculate the values from either end of the 720 degree cycle... especially if you think or expect it to finish on the closed intake valve.

Scott's (spfautsch) comment made the most sense that the LT1 sprays into the open cylinder. The PCM XDF has this set at 180 (#63) WHEN at temp 68C + Up THIS IS THE END OF INJECTION at BDC on the intake stroke.

Now when the motor is colder it brings the EOIT earlier in the cycle SO IT CAN SPEND TIME spraying onto the valve. At this early stage we are warming up so have shitloads of extra fuel not to care about losing it out the exhaust & the extra fuel helps heat the cat and O2's and exhaust etc.

Now my calcs gave a better mixture at idle but i think at wot i was still spraying as the piston is coming back up. I've put it back to 180 BDC value for now, so all the fuel is drawn into the cylinder with the intake inertia.
The LT1 has a fixed position for EOIT only varied by temp.

Also as I have bigger than needed 42lb injectors I'm no where near 80% at WOT & my injection time is a lot shorter as a result.
Idle is around 1.7-1.9ms.

HTH.
Mitch