Cylinder Heads - GM 855 Degree 18 Degree Hi/Lo    The Gm#855 is our new welded, and re-heat treated cylinder head. This is the head that Bill Maropulus is using to dominate the Grand National West series in all of his motors, as well as Ted at Top of the Hill in his SCCA Trans Am GT 1 with Lew Lerimer.    GM 855 Degree 18 Degree Hi/Lo flowed at 28" with radius entry plate 2.180@50 Deg Intake & 1.60@50 Deg Exhaust Valve INTAKE EXHAUST Lift CFM Lift CFM .200 149 .200 114 .300 225 .300 178 .400 277 .400 231 .500 318 .500 260 .600 355 .600 267 .700 365 .700 270 .750 368 .750 273 .800 371 .800