In my listing there are a total of 14 cars with an optional axle ratio ordered. Pontiac (GM I guess) marketed optional axle ratios under three different option codes: The economy axle option, The performance axle option and then special order axle option. The first two were typically a bit lower or higher than the standard axle and special order axles were those further away (up or down) from the standard ratio. If you look at the axle charts in the original MPC (parts catalogue) or shop manual you can see the different choices. With certain drive train combinations you could not order some or any optional axle ratios. Generally speaking the choices were being more and more restricted in the late 60's and especially into the 70's.
There are some odd restrictions on 69 Firebirds, for example: you could special order the 4.33 ratio on the regular 400 but not on the Ram Air IV for some reason.
__________________
My Break Away Squad
1969 Fbird (base OHC, 350, 400HO & Sprint Cvt’s - 400HO & TA ht’s)
1969 Custom S 2dr ht
1969 LeMans (2dr & 4dr ht & Cvt)
1969 LeMans Safari wagon
1969 GTO (2 Cvt, 2 ht & Judge ht)
1969 Cat (3 Cvt’s & a 2dr ht)
1969 Ventura wagon 2 seat
1969 Exec 4dr post
1969 2 Bonnie Cvt's & 2 wagons
1969 Bonnie Brougham (4dr ht & Cvt)
1969 Grand Prix 2 SJ’s
1969 2+2 2dr ht (Canadian)
|