Welcome! I'll chime in on your cam choice. You can make a flat tappet cam work if you're careful about your oil choice, very careful with your initial start and break in process, and a bit lucky. You'll have a better chance of a trouble free engine if you go roller cam with the main line oils available today. Most folks shy away from flat tappet cams, and wouldn't take a used flat tappet cam for anything but an art project.