i've read the gm th2004r can be built to handle more hp than the th700r4 even though it's physically smaller. maybe that's why it was chosen for the available kits.
neil.
Not sure about more, but they can take a lot. The advantage for retrofit in other vehicles is the small external dimensions so they fit without floor modifications in most cases.
First gear is more like 2.74 while the 700 has 3.07 first. Both much improvement over a 2.45 first. Add a bit of converter with the 200 4R and it should work real well. Single unit that is close to the original trans length and the cost difference as compared to the GearVendors is probably not that far off.
