I'm under the impression that a 1959 235 had an improvement that that the 1958 didn't have that made it a better selection for installing in our old Chevrolets.

Can anyone verify the notion and tell us what the difference was?
Thanks,
Charlie

The 1958 and 1959 235 engines are the same - except - The 1959 had a lower lift camshaft and different lifters, improved oiling to rocker arms (more pressure) and revised rocker arms so as to reduce the flow to the arms to restrict the pressure to prevent over oiling.
The lower lift camshaft reduced the horse power from 145 at 4200 RPM to 135 at 4000 RPM and produced more torque in the normal driving speeds. That along with carburetor improvements increased the gas mileage. The new lower lift cam and lifters to match eleminated the lifter leak down during high speed driving that was so common in the 1954-1958 engines.

Thanks a heap, Gene. Your reply was just what I was looking for.
Charlie

Gene,
I have a 1956 235cu in. engine in my 53 half ton. On a recent tour while pulling a steep incline the engine began missing. When I got to the Motel I checked the engine and found #1 & #2 cylinders were dead. I pulled the plugs and checked the plug wires, the plugs were fireing and the color looked great. The engine was still hot nd I didn't have a way to check the compression. The next morning when the engine was started it ran great. Could this have been caused by "lifter leak down" ?

When the lifters leak down it increases the rocker arm to valve clearence and ou will get a loud ticking. Usually engine will not miss.
Just the opposite can happen. The lifter piston expands and gets stuck in the lifter body bore for and holds the valve(s) open causing a miss. When shut off for a period of time the oil can bleed out and things gets back to normal.

Thanks for your reply Gene.