I can get my slant out in 30 minutes flat, I have done it a few times but I might be cheating because my 68 dart has NO a/c, NO power steering and is a manual transmission.
Usually the hardest part is the exhaust bolts because sometimes they are a bit corroded and don't want to come apart smoothly. Other than that, a slant is so simple to remove that even a girl can do it..... In 30 minutes or less