We run our all iron 403 ci SBC, raised runner heads on pure alky using #14 nozzles, running 7.0's and 188 -189mph. However when we raced Salt Lake City, with the track at 4400', and DA at 6500 to 7000', we put #12 nozzles in her, added 4° of timing and a looser converter. Of course we have found the nozzle sizes will depend on the fuel pressure we are planning on running. Don Enriquez runs a low pressure set-up , like 50 to 60#, using #18 nozzles, and a -1 pump.