hello-
Iam looking for some information regarding the expected RPM difference with the 4.88 vs the 4.33 gearing, my tire size is stock. Examples of speed with rpm rough estimates would be best. Say at 110 what would the difference be. Thank you.

 

It's simple, just divide one by the other. So comparing 4.88:1 to 4.33:1, 4.88/4.33 = 1.127. So your revs will be 1.127 times higher with the 4.88:1 gears.
Just curious, why are you comparing those ratios? Apart from the GTUs, which had 4.3:1 gears, all FC's had 4.1:1.

 

ford couriers have 4.875 gears in them, they fit into the FC diff too............................................... ............. not that i've tried it or anything

 

Are you sure thats not for a miata rear diff? We need a long pinion shaft for the N/A diffs.

 

Any whats a Ford Courier for us US spec people?

 

1.6 miatas are 4.4 and 1.8 are 4.3

 

ford courier was an early 80's pick up. looks like the early mazda 2000's. i believe mazdatrix sells the adapter to put early style gears into NON-turbo fcs.

 

ya get ya local machinists to 'blend' the two shafts together