Hi there! Gauge calibration is a meticulous process, and watching the mileage tick up in a stationary shop setting is super frustrating. I ran into this exact situation on my build and picked up a Mileage Blocker from Dynotest https://dynotestpro.com/ to keep the cluster static. It filters out the distance tracking signal while allowing your speedometer needle to move freely across the dial. This allowed me to cross-reference my new cluster readings with diagnostic software accurately while keeping the odometer completely frozen. It leaves no error codes in the computer system, and unplugging it restores factory behavior instantly without leaving traces. It made the entire calibration process smooth, precise, and completely worry-free. I would definitely recommend it for any dashboard project.