Three points:
1. There are profiles other than HTD that will get you considerably higher power density; Gates Poly-Chain GT, for example.
2. You can normally find detailed profile information in manufacturers' catalogs. If you can't find it in the catalog, the belt manufacturer will probably be cooperative about supplying pulley profile information.
3. If you are talking about a drive for the turbo charger, you'll find adequate belts available. If you are talking about a drive to transmit engine power you will need a monster belt - 8 mm will not be heavy enough.