I believe the BCA follows the World Pool-Billiard Association (WPBA) rules, and based on those, you win the game.
The summary is that your shot was 100% legal for the following reasons:
- You called your shot as required by calling (a) the ball (the 8 ball) and (b) the target pocket.
- The cue ball contacted your ball first (the 8 ball), and continued on to either (a) pocket a ball or (b) drive a ball to a rail.
No other details are necessary when you call your shot.
There aren't specific rules I can point you to. It's more that there isn't a rule about a foul for this scenario. It is the absence of such a rule that makes this shot legal.
However, we can look to the call-shot rules to help justify it (emphasis mine):
From the general rules of pocket billiards:
1.6 Standard Call Shot
In games in which the shooter is required to call shots, the intended ball and pocket must be
indicated for each shot if they are not obvious. Details of the shot, such as cushions struck or
other balls contacted or pocketed are irrelevant. Only one ball may be called on each shot.
For a called shot to count, the referee must be satisfied that the intended shot was made, so if
there is any chance of confusion, e.g. with bank, combination and similar shots, the shooter
should indicate the ball and pocket. If the referee or opponent is unsure of the shot to be
played, he may ask for a call.
In call shot games, the shooter may choose to call “safety” instead of a ball and pocket, and
then play passes to the opponent at the end of the shot. Whether balls are being spotted after
safeties depends on the rules of the particular game.
...then, from 8 ball rules (just confirming that the general rules section is relevant for 8-ball:
3.6 Shots Required to Be Called
On each shot except the break, shots must be called as explained in 1.6 Standard Call Shot.
The eight ball may be called only after the shot on which the shooter’s group has been cleared
from the table.
Hope this helps.