I don't think its a deal either without looking inside--yes headers are an issue and a difinant problem if your putting it in a street car like a camaro--engine is not only taller bur wider and 427 parts aren't shelf items like the 4 and 4 1/4 stroke stuff is---I'd opt for a Dart 4.600 bore without the issues of cleaning, inspecting, machining ( and I can do it in house)