Unless you fall into a smoking deal on a usable block, building a 426 Hemi the "Johnny Cash" method (one part at a time) will not save you any money, in fact just the opposite meaning by the end you will be far deeper into it than had you just bought a complete engine. That said there are a couple of advantages; first is that you do not have to lay out all the cash on the front end, second is that you can choose the parts you really want to use and third is that you can make the engine the way you want (stock, stroker, etc.).
You need to know that words "hemi" and "cheap" are never spoken together. Also there is tons of used stuff out there especially from race cars much of which is trash and unusable. Additionally, Mopar made a 426 Wedge which is not a Hemi and more than one new Mopar fan has been sucked into a deal on a "426" only to find out it is not a Hemi.
G2 hemi stuff (426) is unique to it in most cases (crank, heads, valve covers, intake, etc.) but do share some parts from the other big blocks. You need to do a lot of research prior to going down this road, read books, search the internet, ask questions on the forums such as here.
Finding a usable 426 Hemi block is not going to be cheap because those who love and want them snatch them up quickly. Any factory 426 Hemi block (as in one that came in a production car) is highly desirable typically by restorers or people who have factory Hemi cars.
