http://www.wowhead.com/blog=185405/changes...es-in-patch-4-1

You can earn up to 980 VP per week from random Heroic dungeons.
Of that 980 VP, only 490 VP can be earned from tier 1 Cataclysm Heroics. The remaining 490 VP must be earned by running Rise of the Zandalari Heroics (tier 2).
Alternatively, you can reach the 980 VP cap exclusively by running tier 2 Heroics.
The 980 VP you can earn from running tier 1 and tier 2 random Heroic dungeons will count towards your weekly overall cap of 1250 VP.
And, as stated before, if you want to maximize your VP gains, you can still reach the overall weekly cap of 1250 by defeating raid level content.