While I was working on a new engine project, I came up with a good idea which will save some time when you want to make multiple copies of a particular engine. I happen to like making different types of engines for my hot rods but when I come across one I'd like to make for several builds, I first draw up a good set of blueprints with all the measurements I'll need. For the parts like the block front, the oil pan sides, and most of the large flat pieces, I xerox my blueprints onto a full size uncut sheet made for custom shaped stick on labels. I cut out my pieces and stick them onto a flat piece of styrene . I then use the label to cut out the part. If I want to make 3 or more engines, I cut out the first piece and use it for a tracing template like guitar makers use when they make the fronts and backs of the instrument. With one set of blueprints and one set of templates, it serves as a set of masters. You can even precut pieces and store them for later. This is great for someone who builds multiple styrene models and routinely sells them or for someone that likes to build a specific model in a number of colors, shapes, engine configurations or whatever. I hope this helps someone out there. If you need more info on this with pictures, I would be glad to oblige. :)