Topic: 8" vs 9" Differential

[suskeenwiske]

Can someone tell me what determined which Differential Ford installed as it relates to the 8 and 9 inch? Engine Power? Transmission Type? Gear Ratio? Combinations thereof?

Thanks

Ray

[J_Speegle]

Can someone tell me what determined which Differential Ford installed as it relates to the 8 and 9 inch? Engine Power? Transmission Type? Gear Ratio? Combinations thereof?

Engine choice during 64-65 made the difference between  which one of the three rearend "sizes" the car got in a Mustang those years.

RPO could have depending on rear end size and what the owner wanted to order

2:80-2:83-3:00-3:20-3.50-3:89-4:11

All of the above ratios were available in open or limited slip versions

What was standard ratio depended on transmission type and engine type bascially