Possible oiling concerns

Can anyone tell me why my rockershaft won’t sit in the posts?????? I’ve been trying for half an hour now I think and it just WONT SIT IN! It’s 100 degrees out and this thing is being a giant pain in the *** and I literally can’t find any reason why! The rockers aren’t between the shaft and the posts. There’s no tension between the valve-rocker-pushrod connections that could pry it up. It just won’t go in after the rockers have been out on
Did you back off the adjusters? If not, the rockers are holding it off from hitting the valve springs.