I have been told that the firebirds have a different centerlink then the Camaros and it sits in a slightly different location by about a 1/4" towards the firewall. Due to this fact the Oil pan will sit on it and not allow the engine to fully align with the bolts on the mounts. The Oil pan has to be modified to clear the centerlink.
Hopefully you verified that the oil pan is not hitting something already?!
Brian Hobaugh SCCA National Tour June 2014
First Hemi 'Cuda Convertible Ever Built
Short clips: Goodguys Pleasanton autocross and pit videos
Threaded Mode