According to some sources, only ~50 aircraft were transferred via this ALSIB route before it was decided the engines could not handle the cold of Siberia. "The Americans had briefly attempted to fly P-40s along the AlSib (AlaskaSiberia) Trace from Alaska, across Siberia and then to western USSR. However, the fighter?s Allison engine proved unable to manage the extreme cold, and this route was abandoned for P-40s following the delivery of just 48 aircraft." This is from an Osprey publication.
Interesting. Plenty of Airacobras were transferred via ALSIB-route...
Cheers,
AaCee