Sounds like someone here needs a copy of the competition prep manual. When I did my 1300 Mk3 engine back in the 70s it said take .150" off the head. And that was a 1300 small journal head! Clark Clark W. Nicholls 1972 Stag (LE7931E), 1974 Spitfire (FM14571U) and 1 rusty GT6 needing new owner "Reality, it's not what you think."