Jim,

Here's a discussion on Chevy Talk that says compression on a '54 235 is just under 125#.

http://www.chevytalk.org/fusionbb/showtopic.php?tid/282437/

So low 80s# on that 'engine might be a clue.

According to this even a '48 216 has compression pressure of 110#: http://www.secondchancegarage.com/public/361.cfm

In the past I've adapted a spark plug base to accept compressed air. If that air is whistling out the carburetor or exhaust pipe(s) with the valves closed a burned or bent valve would be a suspect.

Last edited by yar; 10/03/2017 12:33 AM.
Ray