Hi Mike,
Possibly...with a 1960 235 you could have hydraulic or solid lifters. Do you know which you have? This sounds valve related. You could rotate the distributor until the rotor tip points to the wire connection spot for the cylinder in question (number 5? it sounds like) and check to see what your valves are doing there. If you're seeing the lifters push up the rocker arms and seeing the valves open/close, that's worth knowing. Once around 1980 I had a valve spring break down low...just messed the spring up enough that it no longer was doing its job but the engine was still running (except for that cylinder). Grab the valve springs for that cylinder and try to move them by hand. If one wobbles, then there's the problem. Also if you have a way to send compressed air into that cylinder, get the piston at top dead center (look for the spot where the rotor will point to the place where that wire connects to the distributor), push air into it and listen at the exhaust pipe and carburetor throat. You can tell which valve isn't doing right by that approach. Please let us know.
Sorry 55 first series...I was typing as you were posting...
Last edited by Jon G; 05/01/2024 2:27 PM.
