Could anybody tell me the gear ratios of the allisons behind 5.9's in buses. And what kind of power can they handle. I'm suprised I haven't seen them used in swaps since the combos are pretty easy to find.

 

The old AT545's were pretty tough, but they lack 2 things dieselers like: Lockup converter, and overdrive.
Transmissions << Atlantic Detroit Diesel - Allison
Just because it can take 235hp in a 25k pound truck doesnt mean it cant take 400 in a pickup. Suncoast makes a tight stall for them too

 

Anybody know if 1st and 2nd are any lower than the newer Allison's in GM pickups. If they are you could use a higher axle ratio to make up for lack of an overdrive.

 

1st in the Allison1000 is 3.1
1st in the AT545 is 3.45
You would need higher axle gears to make it work right. It's a simple solution for a cheap to buy tranny.

 

Is there any other
options for transmission

 

You can get higher gears but I would still rather have an OD AND lock-up.