Does anyone have an idea of how much performance the 4.1 Recipe on gnttype.org could be expected to produce? It sounds straight forward enough, I was what difference the extra cubes would provide. I wouldn't choose to start a project with a 4.1 normally but the car I'm getting (87 GN T-Top) already has this setup. I need to choose a cam and turbo to complete the package and am open to any suggestions or opinions on what parts to consider. The car is intended mostly for daily street type use (but will see the track more and more as is typical), with the occasional education to challengers. Thanks for the help. :biggrin: