74 Charger interior fuse box issue

My 74 Charger has a loose fuse box sometimes when I turn the car over it starts but stalls when the key goes back to the Run position I checked everything and then I found that if I pull on my fuse box a little bit it will stay running in the Run position I'm having a hard time getting the fuse box out so I can find out my situation is it clips I don't see any screws what holds that fuse box to the bulkhead firewall side

Could be a ground on the inside or a wire connection at the engine firewall side.

If my 72 is like your 74 then you should have two of these clips (this is just one at different angles).
I took this out of my original bulkhead to put in my reproduction bulkhead as they are not as good as the originals.
I was experiencing the same issue as you.