I agree that the "LEA" on the tag signifies a 235 motor built for the 6000 series of trucks in 53'. The "A" designates a Flint-built engine.
With the 6000 series in mind you may find something useful in this page of engine data from the 53 resto-pack from the Keith Hardy site.

http://chevy.oldcarmanualproject.com/chevyresto/53141.htm

Again congrats on your find. Seems almost like a time capsule.




"Nothing astonishes men so much as common sense and plain dealing." - Ralph Waldo Emerson