block.json

{
    "name": "acf/car-details-condensed",
    "title": "Car Details condensed (ACF Block)",
    "description": "Display car details in a query loop.",
    "category": "demo-acf-blocks",
    "icon": "car",
    "acf": {
        "mode": "preview",
        "renderTemplate": "template.php"
    },
    "style": ["file:./style.css"]
}

template.php

<?php
// Number field.
$mileage = get_field( 'demo_vehicle_mileage', $post_id );
?>

<?php if ( $mileage ) : ?>
	<p><?php echo esc_html( $mileage ); ?> miles</p>
<?php endif; ?>