I have a chance to buy a '40 Flathead. Well I have my choice of 2 motors. Both rebuilt and complete. The price is really fair. Actually really really fair. Are there any disadvantages to this motor in a hot rod as opposed to a later model flatty? I have a 32 frame and a model A body to drop it in. This will be a late 40's early 50's hot rod. Wire wheels, banjo rear, top loader trans, the works.
Most 1940 vintage flatheads will be 221, some will be 239. If 239 and actual 1940 age, will have "99"stamped on upper surface... If engines are just FROM a '40, could be anything, so look on bells for "59""
They are "From" a 1940. Sorry, forgot to clarify. I believe it has the 59 stamped in the top of the bellhousing.
Look for 99 stamp, 59 casting, marks on head, raised manifold surface, shape of block between manifold and front cover...that shape is "J" on earlies, "/" '46-8...flathead in a 40 could be anything, but most replacement engines were 59's.
1939 and 40 are not model 59 very similar but not quite the same. I was confused for some time that a lot of the parts etc. that I found for a model 59 were not the same as my engine until I found out mine was a true '39. '39's and 40's have no 59 cast into the top of the bell housing, are 221 or 239 c.i.d. the 239's were identical to the 221 but had their sleeves pulled out and used bigger slugs. Mine is a 239. There's almost always an advantage to later model engines but no reason specifically to turn down a good deal on a true 40 model 59 parts do interchange with them for the most part.
Prewar 221 and 239's both were made with and without sleeves; A 221 can go to 239 bore, but 239's have MUCH thicker bore castings, thicker than 59's, too. There are basically 2 generations of prewar 24 stud castings, both different from 59's externally and in valve angles, but the external difs are fairly subtle... The prewar 239 was always the preferred block for big bore/fuel racing because of its thickness. Prewar 239's, unless they have the 99 stamp used on many '39-40 ones, are externally indistinguishable from 221's.
All the prewars have thge distinctive front slope difference from 59's, roughly '39-40's have the two lower freeze plugs on each side on pan rails, visibly marked by bulges on sides of block, and '41-2's have the raised pad at manifold surface. Outer bolt ons should be ignored--any mix is possible
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