I was going to breed [color=red]Pandora’s Box to A.P. Indy, which would be a linebreeding as her grandsire is Seattle Slew (I), the sire of A.P. Indy. DI was 47.00 for this breeding. But last year I bred her to NCh. National Post, which is not related to her. So I don’t know if I should look for a stallion with Seattle Slew in his pedigree, or outcross. She has one of the nicest pedigrees among my mares (because most of my broodmares are created 
). And she is Gr. 3 Stakes level on dirt, sprinter and classic. She is due 5/4/16, so I have some time 
Would be nice to find a stallion that was successful at the age of four and five.
Golden Text is an AP Indy son at stud.
I know, but with their height the foal would be between 14.3h - 15.2h… I would prefer a taller one, maybe I will breed to one of the new famous stallions.
If you want to line-breed, I think the recently retired GCh. Mantle of Power might be worth looking into. You’d get a 3x3 to Seattle Slew and a 4x4 to Highland Rogue. You have the same problem of potentially getting a small foal, since the sire is 15.1h
Tallest stallions are as follows, if you’re interested:
Gilded Saint- 17.3h
Strike It Rich - 17.2h
High on Love - 17.2h
Sixth Day - 17.1h
Foolhardy - 17.1h
Cryptic Ballad - 17.1h
And then there’s a bunch of 17.0h boys as well.
I guess I’m not clear… are you looking for suggestions in general? Based on race performance? Height?
Thanks for the ideas! I’m concerned about height because I have this little mare [color=red]Mimosa Lake which is now 15.0h, and I’m sure that she was below that… anyway, she didn’t win anything for a long time and I thought that this is because of height, but I see now that she might be a late maturer.
Horses can win at any height. Shorter horses have shorter strides (obviously) but also have a faster stride rate. Taller horses have longer strides but a slower stride rate. So if you have the right combination of numbers, it doesn’t matter what the stride length is.
This reminds me of “races” that I had with friends during some holidays many years ago, we had three horses - a fat konik polski, arabian-haflinger mare and a shetland pony. We used to race on a meadow near a lake and the most ambitious was that little shetland pony, she won almost every time 
Also, the mare might still be immature. Thus, her shorter height is less indicative of her racing ability, and more indicative of whether or not she has “hit” her peak. She may be a late bloomer. (It happens)
And here is something that explains it all! 
horsetalk.co.nz/news/2012/01/200.shtml
From the article:
[i]
"The genes of a single Shetland pony mare gave the thoroughbred its speed, British researchers say. "
“Scientists have traced the origin of the so-called “speed gene” in thoroughbreds back to a single British mare that lived in the United Kingdom about 300 years ago.”.[/i]
Thanks for your advices about the mare, I decided to breed her to one of the new stallions, probably Empire Maker 
Wow I didn’t realize my boy Saint was one of the tallest studs in the game, no wonder some of my foals are predicted to be 17.2 at maturity.
My little stud is a shorty and he used to win a lot of races.