i am looking into getting a 9-bolt, with 2.77 posi. I will want to put a 3.45 gear into it, will i have to buy a different posi unit, or can i just get a spacer?

oh yeah, with around 250hp at the wheels, will a 9-bolt hold up with slicks??

 

as long as the gears are for the same carrier (not sure if 9 bolts have more than one carrier or not) then they should just be direct swaps, the 9 bolt should easily hold up to 250hp

 

Sorry, you're gonna have to use a 3 series carrier. 3.27 & 3.45 gears won't fit on a 2.77 carrier. The only person I know of working on a spacer is miles @ www.9bolt.com but it is not for sale yet. I would think that a machine ship could make one pretty easily if you acqured the measurements for them. Then you wouldn't have to get the 3 series carrier.
Draino

 

I emailed him to see when it will be ready for production.