http://www.vanpeltsales.com/FH_web/flathead_specs-85to100mid.htm good question. I had to look it up...hope this helps
A lready B cracked! These were replacement motors installed after the war. I was told by elderly gent that since car production was behind from the war effort Henry would replace your worn-out flattie with a new AB short block (minimum) + what ever else was needed for 80.00. Ford used whatever you had that was good and added the AB to it. Told it was done in one day! Merc's got the same AB, i.e, no Merc AB's.