Engine Lock Down

Hey everyone I need some help. I’m trying get my new build together and when I tighten the bellhousing bolts it locks down the engine. If I back the bolts off just a hair I mean like two finger nail thickness the engine will spin. I cannot for the life of me figure out what’s wrong. I believe the convertor is in all the way because there is space between the flexplate and convertor. Please help!! Lol