I feel it's a GM Corporate 10.5"....my car is a Norwood June customer ordered. Firebird production was supposed to end around March '69 due to one of the plants being on strike. Norwood was chosen to absorb the Firebirds from the other plant and production was pushed out to November '69. Some '69 models were fitted with modified parts (mule cars) to set the '70 model year design. After testing, the cars were sold. Too bad there wasn't an odometer disclosure at dealerships. If so, we could tell if our car was a test. The Trans Am did not sell a lot and remaining components may have ended up in other cars. I'm guessing a lot of mid-year '69's were NOT number matching because of this. Just find an owner that complained about mileage on their new car when they bought it. **Theory**