The next one is not so much fun. There's a long tall oil passage which starts at the top of the engine at the oil sender and goes all the way out the bottom, if the main bearing cap is removed. However, there is supposed to be an oil plug "in there." It's a press in plug like a tiny freeze plug. You can tell if it's in there by removing the oil sender and sticking a straight wire like a gas welding rod down there and measuring how far down it goes. I'll have to search and find out what that measurement "is"
Also do you have ARP or other main bearing cap studs? There has been some oil pump interferance issues, causing leaks and cracks / breakage at the pump mount
Also there is a possibility of some pumps and some pans interfering, which can damage / break a pump