Thread: 21 Stud 37mod
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Old 01-02-2021, 04:17 PM   #41
38 coupe
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Join Date: May 2010
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Default Re: 21 Stud 37mod

Originally Posted by Ol' Ron View Post
Well you learn sumpin every day, till they throw dirt on ya. So your saying that early 91a blocks were small bearing ones. Did they have a different prefix number?? interesting.
Thanks Gramps
Annoyingly Ford called both 81A blocks. The Green Book lists the 2.4 inch main version as 81A-6010-A for 1938 only and the 2.5 inch main version as 81A-6010-B for 39-42*.

*really annoyingly Ford apparently didn't change part numbers when the following three changes were made around the 40-41 model year change over to the blocks: "raised" intake surface (actually shrunk outside the gasket area), elimination of the core plugs in the oil pan rail, and sides of the block curved up to the exhaust ports.

I only know this stuff since I really like 38 Fords and trying to figure out how to make a correct looking 24 stud motor takes a bit of reading. I appreciate your experience and willingness to share, please don't take my clarifications as anything bad or mean.
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