Disaster Strikes!!!

[Frank_S]

Okay, last night I pulled a major digger and knocked over one of my Ricks, producing a four inch horizontal crack between the fingerboard and the neck on the treble side. I can see a slight space, so I know it's not just a finish crack.
Luckily, it did not break off the headstock.
It could probably be glued and clamped but I'm not sure how to get pressure on the edge of the fingerboard and neck where the crack is.
I was thinking about making a c shaped wood block to press against the neck and then C-clamping it. I'm not sure if that will provide enough pressure. The rod is not exposed, and there is no twist in the neck yet. I slackened the strings slightly, but not totally. I was afraid a sudden tension change may damage the guitar further.
I've reattached two headstocks to other guitars, so I'm confident I can fix this, unless there are other factors I'm forgetting. Any advice or thoughts would be appreciated.