Traxxas big block conversion kit components required to install a big block engine in your Revo model. The following engines are known to work with modification: Nova Rossi 528, Nova Rossi .21 P-5, Picco .21 Maxx, Sirio S23TX, Sirio S27, and Team Orion Wasp .26. The following engines are known to NOT work with this conversion: Thunder Tiger Magnum Pro 21, Associated Pro 21R, O.S. .21 RG and O.S. .21 RZ INCLUDES: Forward only conversion kit Universal engine mount Manifold with gasket and spring Flywheel and clutch nut Forward only shaft Miscellaneous hardware required for installation Required Parts A big block engine with pilot shaft style crankshaft