Easy there man, no need to get hostile. From you initial post there's no way of knowing what you are starting with, what your goals are, or what you know about the subject. BTW what are your goals for this new engine? What are you planning EFI or carb?
There's also a big difference between "new everything" and "canget most parts used". Which do you want an all new engine, or a good engine built using used parts? Both work, both can give good results, but you have to be careful with used parts. IE: Those bare heads, do you know anything else about them?
The only issue with your shorties is the primary diameter, do they flow enough for the 347?
The reason I suggested looking for more info on google and MM&FF, as well as various Mustang forums, was because not many people on this forum have personal experience with a 347. There are a few, but not many. I'm not saying don't ask just making recommendations that could help you find the information you were looking for.