I have a 2003 gmc sierra with a 70mm journal bearing turbo but looking at getting a 72mm ball bearing turbo, would i have to get the truck retuned?

 

Yes, you would want to get it re-tuned/checked over.

A larger turbo is going to move more air at any given time so at least watching data logs should be done to see what may need touch ups.

 

That is what I figured. What about a built trans with 3000 stall vs stock trans and converter

 

What are you asking though?

The stock 4L60e with stock converter is weak, I'm sure you know that already. A built transmission with a stall that matches the camshaft is always going to be better. Doing that change would need tuning as well.

Or most just 4L80e swap to be done with it, because it's much stronger and a stock 4L80e is super tough and costs way less than a really well built 4L60e. There can be added costs with the swap if you need a new driveshaft made or want to have a higher stall converter or swapping rear end gears to better match the transmission/tire choice.