The N1 Race Block Is A Rb26dett Designed For Use In Race Cars Running On The Grueling Nuremburg(sp?) Ring In Germany. It Is No Different Internally Than A Stock Rb26 With The Exception Of A Few Things. These Things Are Higher Quality Pistons, High Volume Water And Oil Pumps And Stiffer Valve Springs. They Also Come With Upgraded Turbos. N1 Was An Inhouse Racing Package.
Yes, Everything From This Engine Will Move Over To The Rb25 If You Can Get Your Hands On This Stuff.