I recently bought a 69 camaro and am trying to find out which rearend gears are in it. Is there a code in the production codes on the firewall? Or how do I find it. Thanks in advance

 

there is a number on the passenger axle tube that should tell you the factory axle ratio but the gears could have been changed so that it number would be useless.

here is a link to site with the code info and location of the numbers

1967-69 Camaro Drivetrain Decoding


(i cant believe i beat 69 to the punch with a link)

 

^ Hee, hee....cuz I didn't need a link!
The numbers on the housing will tell what the rearend originally came with. The gears could have been changed out over the years, so the only way of really knowing for sure what you have is by removing the cover and looking, or giving your wheels the twirl test. If you have a posi rear, jack both wheels off the ground. Turn one tire one full revolution, and count the number of times the driveshaft turns. For example, if the driveshaft turns 3.5 times to the tire's one turn, you have 3.55 gears. Now if you have an open diff rearend, jack only 1 wheel off the ground, but turn that tire two full revolutions instead of one, and count the number of driveshaft turns.