Crystal oscillator replaced with exact frequency for clock?
This crystal (61.44 MHz) is used in video board generator. It has no relationship to Z80, which uses a different 6 MHz crystal, so your reference to CPU confuses readers.

As shown in the schematics,



the crystal is a part of a sophisticated HF-oscillator, so a VCXO-type programmable crystals/oscillators will unlikely serve as direct replacement.

You have two basic options, either to find this vintage crystal (or similar one) and hope that its ESR will match the original, and the circuit will start oscillating. Or replace the entire generator with a modern programmable oscillator, program it to 61.44 MHz, and drive the isolating transformer T1 directly with modern electronics. You might need to keep the Q2 as power amplifier.