Bad news on the tranny. The LS1 tranny is different than the one in your 97 Tahoe. Bolt pattern is changed, depth of the torque convertor, different torque convertor, different flex plate, different stator on the front pump and different input drum in the tranny. Get the trans with the engine and save money and headaches.

any drive shaft shop can modify your shaft if needed. You'll have to get your engine in and see what you need afterwards. It all depends on the placement of the engine that will determine if you need shaft work.

I have a 34" radiator and a lower hose from a C2500 worked perfect. I used a f-body upper hose from a car without p/s cooler and then added the cooler. I cut the hose for a perfect fit. Definitely easier than it could have been.