No. Yes. Yes.

From Tim's website
http://www.1954advance-design.com/Web%20images/1958-60-rocker-oil/1958-rocker-arm-lubrication.html

1954 and later 235 car (not truck) engines with Powerglide had hydraulic.

Even with cars, there are noise issues with making 235 hydraulics work like expected. Lots of reading and ask questions before going this route. Many old truck owners like the light clacking of solids.

"Adding CFM to a truck will only help at engine speeds you don't want to use."
"I found there was nothing to gain beyond 400 CFM."