VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Differences between 1938 and 1939 motors

Went through the DMV thing because the CA title had the engine ID and the engine had been replaced. Family history said the motor had been replaced in the 40s. When I went to look at the block casting number it is 838941 - so a 1939 motor. It has a hand stamped ID on the plate by the distributor. Wonder why the replaced the motor so soon?

The Body ID is 6HA05 21586 so it was built in May of 1938

Anyway, are there any significant differences between the 38 and 39 blocks?

I really can't say why the engine was replaced. The 1939 block was sold as a replacement for 1937 and 1938 models after 1940. My guess it was replaced some time after the war like 1946 or 1947. If the original engine had like 85 or 90,000 miles and was knocking and the rest of the car was still pretty good they probably decided to replace the engine with a new short block which camw with no number stamped.. There is a date code on the side of the block down near the distributor.
There is really no difference between the 1938 and 1939 block other than the way the vacuum advane is bolted to the block.
There were some changes to the "bolt on" parts but they would have been transfered from the 1938 engine.

That makes sense. I guess I should have paid more attention to the stories Great Grandpa Walt was telling about the Chevy. It never crossed my mind then that it would end up in my garage.....

Some more info.
Your 1939 should be one of the first ones to have some mid-year revisions made.
On April 21, 1939 the instrument faces changed from brown to cream with red pointers. The head light rims changed from painted with a thin chrome bead to all chrome. The Master DeLuxe models came with the bird hood ornament. The hood side moulding stripes changed from red to cream. The top of the grille bars changed from black to cream.

Great your 38 remains in your family.