Well kinda a long grey story, never less I'm going from a 475ci class to a 410ci small block only class, have fought for two years that cubic inch is cubic inch big or small block, they won't budge claiming I'll make so much more torque with bb, never less it is a Chevy 400 run class so had a 383 kicking around and got the go ahead to run what I call mopars 383 mid block kinda like the Ford 351 so just throwing together a used parts special, yet finding 383 parts is a struggle