'69 Valiant 2DR Project

I'm getting pretty good at pulling and installing the trans. Pulled the trans yesterday and took out the 4k stall converter. Today I put the 3200 stall converter in and bolted the trans back up. I spun the motor over on the starter before I left for work. Spins great but the starter gear is getting hung up and doesn't retract.
Does a lower stall help build boost earlier?
I'm turbo dumb lol