Entei: 2.1m and 198kg
Lion: 2.5m and 250kg*
Minivan: 4.6m and some couple of thousand kg I'd guess
Unless you expect me to believe the given height of all pokemon is strictly vertical (but then Yanmega makes an idiot of you; I'm reasonably certain the height characteristic measures its body length) and that vertical height is the only relevant factor when determining the 'size' of something.
But if you continue to assert that point, then I guess Entei is roughly the same vertical height as a minivan. You know assuming it stands fully upright and makes no effort to hide in the grass whatsoever.

*High range admittedly
Measurements given in metric because better/what game freak actually uses

Entei is the largest of teh three and is smaller than a real life male lion.
Minivan my arse.

Whoa man they never just give you the final form. You'd first obtain Ridley in this form: http://images2.wikia.nocookie.net/__cb20100828123...