International Tractor Runs ROUGH... (Part 1: Diag & Teardown)

My neighbor s 1975 International Harvester farm workhorse doesn t have all its horses... Out of 4 cylinders, 2 are very low on COMPRESSION. What could cause two neighboring cylinders to lose compression? Upon teardown, it becomes clear that my initial diagnosis was not accurate... Some more parts may be required! IVAN S PICO WAVEFORMS: https://drive.google.com/drive/folders/11g9hZM6p2PF0-SaSQWquhn07p4aZq6V5?usp=drive_link PHAD PRESSURE TRANSDUCER: http://www.pinehollowdiagnostics.com/phad-pressure-transducer.html Enjoy! Ivan