The Nissan GT-R VQ38DETT engine is the big boy here at Synergy Engines.  We can start with a OEM Block and Heads and add Sleeves and a Line Hone and have a very respectable engine.  If you are interested in CNC Porting and Seats we have those options as well.  We do require a core for the project, but we also quote an "All New Parts" build.   With different block options, strokes, and rod length options, there are many ways to get creative with this popular platform.