Ok I tired understanding the chart on the FAQ section and I still don't have a clue. My mind is mush right now! Ran a search and did not find anything conclusive.

I have to go to the tranny shop in morn. New tranny has a major issue. Anyway while the tranny is out I want to have him swap me to the correct speedo gears for my new 3.73 rearend.

Car is a 1987 v-6 car. (700r4 obviously)
Came with a 3.42 rear.

I now have a 3.73 rear.
I have tires that are 25.7 inches tall.

What speedo gear combo do I need to have a correct speedo reading?

I found in a search where someone stated the factory speedo gear combo is as such:
in a 3.42 car... 15/41
in a 3.73 car... 15/45

So do I just go with the 15/45 combo to get a correct speedo reading?

 

45 sounds right if i remember correctly thats what i put in mine.

 

15/45 will fix you up for 3.73's

 

thanks guys!