On Mon, Sep 6, 2021 at 2:48 PM William Jahn <willjahn975 at gmail.com> wrote: > pipe. The 73 was an X and 72 a U engine yet both had the same rods and > pistons Bently shows the U having 7.7 compression and the 73 7.3 yet I > can't see how , the Bentley does have some info wrong . Different deck height and/or chamber size will change CR. Max