My reproduction manual for L-head continentals show a F400 power unit picture but no specs. It does show specs for 4 cyl f series f124, f135, f140, f162, f163. And F series specs in 6 cyl. f186, f209, f226, f227, f244, f245. Look at montesequipment.com they specialize in older continental motors. You are lookn to rebuild, you will also need a manual. I got mine at jensales.com and there also manuals available at wisconsinmotors.com Hope some of this helps.