Need assistance on information 69 Firebird
 

My brother has his original 1969 Firebird 350 HO with factory installed Ford 3 speed in color carasoul red. We have been trying to find out why Pontiac installed a ford 3 speed and not GM brand and how many of the 350 HO in this color had a 3 speed. If anybody knows this information or where we can go to get it we would appreciate your help. Thank you