The Murnan Modified RBM3 engine developed by Uriah Murnan at Murnan Modified Motors. The .12 engine uses the RB concept T9 as a base. The engine has undergone extensive internal modifications to make the most powerful .12 engine to date. Not only is the engine extremely powerful, it is also very fuel efficient. The smooth, yet aggressive power delivery will leave nothing to be desired. The metal carburetor insert is a special shape to improve airflow. The engine comes with a ceramic main bearing. 5 out of the top 10 drivers at the 2009 US Nationals used this engine. Compatible Pipes: Novarossi 2630, 2652, 2601. RB2604 Engines will be in stock November 7, 2009