So today I was told that 1970s era 427 engines made in Canada were externally balanced engines. Engines made in the US were internally balanced for the 427. I have a big flywheel from a 427 that is externally balanced. Plan on using it on a 454 with the original crankshaft. Local machine shop said they can check the balance for me. I would like to have an idea before I drop it off. Do they share the same external balancing?