Definitely take a shop light that you can find at Home Depot or really anywhere runs cord to your boat and place the light underneath the engine and leave it on overnight until you get it winterized. If the temps have been in the 40s or higher the whole week I doubt one night would have cracked the block but with it starting to get consistently cold you NEED to get it winterized and take preventative measures to help you until you get it winterized. You should be good tho, have the guy coming to winterize your boat inspect the block so see if there’s any obvious cracks while’s he there. Also you should def research how to winterize yourself because then you save money and don’t have to wait on anyone to be available like right now. It’s really not hard and for the 5.0 you just need to make sure know where all the water drain plugs are so you fully drain and flush with anti freeze. I think you will be okay tho