71 Duster 360 turbo build

Well I have fuel dialed in and boost up to 10psi. Added some timing back in dropping from 38 to 22° at 10-12psi and the duster was making some steam. Then I did a short pull in 2nd gear and something seems to have let go. When I let off I heard some kind of loud mechanical whirling noise “spooling down”. I thought, and hoped, the turbo had gone out but it seems to be fine. The car still runs and drives pretty strong, but seems a bit lazy getting into boost. I’m thinking I better pull and inspect the trans because I have no idea what that sound was. Looking at my logs the converter is flashing to 5k rpm when under boost so I’ll need to have that tightened up while it’s out.

Earlier in the drive I hit overboost in 1st gear about 3 times in a row pretty hard, and am wondering if that could have hurt the sprag. It will be time for a billet front drum if I decide to open it up. I was really hoping to make it to the strip soon.