LEA is the 1953 Engine Serial Number prefix for a 235 engine installed in 6000 series truck.

The "over stamp" is possibly an indication that it is a replacement engine.

What is your title/registration vehicle ID?

http://www.1954advance-design.com/chev-specs/1953-Chevrolet-t-and-c-ser.pdf

Find and post the head & block casting codes (and date casting codes). This will confirm the pedigree of the engine.

Cheers

By the way, what bubbles do you make?