5 (S/S) 1400 260 325 This is the speed breed. It gets a double dose of speed. 1400 is the health that pet will have at max level, 260 is the power and 325 is the speed.
6 (H/H) 1725 260 260 This is the health breed. It gets a double dose of health. 1725 is how much health it will have at max level. The first 260 represents the power and the second the speed that it will have at max level.
7 (H/P) 1546 289 260 This is a duo breed. It gets one dose of health and one of power. Again, the numbers represent the health, power and speed such a pet will have at max level.
8 (P/S) 1400 289 289 This one is a power/speed breed. Once more, the last 3 numbers represent the Health/Power/Speed.
1 (S/B) 1465 273 289 This last one is a half speed breed. It gets one dose of speed and the rest of its stats are balanced.
The first number in each set (5, 6, 7, 8 and 1... though I don't think the 1 is an actual breed... are you sure that shouldn't be a "10" instead of a "1") are from one method of saying what breed the pets are. The letters (S/S, H/H etc) are from another method. Personally, I find the letter method less confusing than the number method and when talking about a pet would only refer to the letter code for its breed.
Basically, when using the letter method, "B" stands for "Balanced," "H" stands for "Health," "P" stands for "Power" and "S" stands for "Speed." Both a P/B and a P/P are technically power breeds, but the P/P would have more power than the P/B because it gets a double dose of power.
The number method gets even more confusing (to me at least, though I know that there are people who prefer it to the letter method) because there are technically 2 numbers that represent each breed and some people list both numbers (for example: 3/13) when talking about that breed. They do this because the only difference between a 3 and a 13 is the gender (a 3 is a male and a 13 is a female).
I hope this helps and is not just more confusion for you.