I know there is a tech article about this but it don't understand it completly. Im hoping someone out there has done this swap and knows what Speedo gear i need . I am putting an 9 bolt 3.27 posi in my 86 iroc with a 700R4. I think(don't quote me on this) that i have 2.73's right now. I know for a fact that its an open rear and that its harder than i would like to spin a tire with. Anyone got any help for this one. Im really getting anxious to feel what the car drives like with this rear. I've never driven a car with a posi (this being my first "performance" car).

 

bump

 

No ones got a suggestion for this?

 

You'll have to change both speedo gears. There have been a lot of posts on this. You are lucky you have a 700r4, its much easier to find speedo gears for those, rather t-5.

 

15t Drive gear 8642620

39t Driven gear 1359273