The NAR and Tripoli both have programs for obtaining high power certification. You need to join one or both of these organizations if you want to fly high power rockets. You must be at least 18 years of age to become high power certified. 1.4 I would like to get into Large Model Rockets. The following manufacturers currently have NAR certified E, F and G motors, as indicated.
Several manufacturers sell rockets designed for E through G powered flight.
Refer to the previous list of addresses and get a few catalogs. R.m.r readers have recommended kits from NCR, THOY, LOC, Aerotech, Vaughn Brothers, and others. Use CA and epoxy rather than white or yellow glue. These rockets will have to survive much higher stresses than smaller model rockets. I don't know.