I'd advise your buddy to buy a nice car. (Many quality cars are for sale) and put in the LS9. That is going to be the least expensive route. When you sit down to plan your build and your first order of business in an LS9, well that snow ball is going to be quite large. Well in to the six figure range with many a Saturday night pissing and moaning about why that brand new part doesn't just bolt on.