Heatran is a basic Pokemon. "Put this card onto your Active Heatran. Heatran LV. X can use any attack, Poké-Power, or Poké-Body from its previous Level". so yes. you can. as long as its heatran! source
http://www.pokemon.com/us/pokemon-trading-card-game/database/
and my knowledge.
Well actually, an ex card has the same value as a Lv. X card. So you can just put the Lv. X on a regular Heatran
How to change your username How to add a user avatar Why was my post hidden? The points system Question etiquette Flags vs Downvotes Anime FAQ
Type a Pokemon name, type, move or ability to see instant results.