It's a 305 in a 1984 Chevy Caprice Classic. It has the old biga** mounts, which I think it would be a major pain to pull the motor to cut the mounts. Plus I think I may have to cut too much out for them to fit. See attachments.
Also I would be doing this for a welding class, so I should have everything I need to fab. them, including a tubing bender and a Bridgeport milling machine. I went with the gasket idea and came up with 1-5/16". I may go bigger later to allow for the tubing.