steering column removal

Forgot to put exaust manifold in place before putting head on...now can't get manifold on. If I remove the head, won't this ruin the gasket. That's why i wanted to pull the column but can't fiqure out how. It' a 64 cuda with manual steering and I removed a clamp at the end of the shaft. This exposed the the "split" at the end of the shaft and I see the splines that this split end slide over. I don't see any roll pins or any other methods of this being held in place. I can move the shaft up along those splines but only about a 1/4 inch. It's a 340 with the hipo exaust manifolds. Any pictures of manual scans would be a great help.