Since the thread hasn't moved yet I will jump in. The concern about spring size would bother me if I was going to do a lot of hot rodding. If you plan on daily driving with no burn outs or sticky tires, the stock springs would be OK. You can always add one more spring clip to the front half to help hold the pack together better. And as long as you are running a 2.73 axle in a heavy truck, spring wrap probably won't be a problem. Beings this is a suburban, I would bet the spring are fairly heavy already.
So save a bunch of setup time, a T350 trans will be a better choice.
(
http://700r4.com/faq/ratiocmp.shtml ) It doesn't have the lowest first gear ratio, but you won't have the expense or weight of a 700r4. Stay away from the powerglide, they are outdated and like starting in second gear all the time.
