We're dealing with a very basic engine design that didn't undergo any noticeable changes in engineering or construction methods from the 1920's to the 1960's. Look at a 194 or 207 engine from 1928-34, and a 235-261 from 1962. They will all be instantly recognizable as being a Chevy stovebolt type engine. There was a compression increase or two to take advantage of the improving quality and increasing octane rating of gasoline, but the basic layout of the ports, combustion chambers, piston design, etc. was virtually unchanged. The 3rd.-generation inline 6 from 1962 to the mid-1980's incorporated a lot of the small block V8 technology, but even those engines take a lot of major modifications to see a dramatic increase in performance.
You really can make a silk purse from a sow's ear, but it makes the pig look funny, and it doesn't hear well afterwards!
Jerry
