What stall speed do I need

I was using a 3400 currently and a guy told me I may want to go with a 3800 with the new setup. I just wanted to see what others might recommend.
I know for sure I won't go lower than the 3400, but if more will be better I will go up

If you just "guess" and take recommendations from he said she said, you could very well be leaving a lot of driveability AND performance on the table.

Your best bet is to call a converter builder after the engine is done and dyno'd and have one specifically built for your car. My theory is do it once and do it correctly the first time, especially with a converter, it can make or break your combo..

They will want tons of info from you, weight of the car, intended usage, complete engine specs, trans, rear gear, tire size and on and on.

You would be best to call a Converter builder give them the exact specs of your engine/car and have one built specifically for you.

Mad Dart is dead on.