The most reliable combination in Stack's operation is with jockey Seamie Heffernan, who is one of Ireland's most experienced riders. Together they have clicked in 8 races from 56 — winning about 1 in every 7, or 14% of the time — and that consistency suggests a genuine working relationship rather than a casual arrangement. When Stack puts Heffernan up, it's worth taking notice.
One area where Stack genuinely stands out is when the ground is soft and wet underfoot. In those conditions his horses have won 3 from 16 races, a win rate of 19% — closer to 1 in every 5 — which is meaningfully better than his overall average. That's not a fluke; that's a trainer who either targets soft ground deliberately or prepares horses particularly well for it. Either way, when rain has been falling and Stack has a runner, that's a combination worth watching.
Sixty-two winners in four years won't put him on the front page, but it tells a story of steady, purposeful progress. Training racehorses is a long game, and handlers who build incrementally — rather than burning bright and fading — tend to be the ones who matter a decade from now. Stack looks very much like one of those.
| Course | Races | Wins | Win rate |
|---|---|---|---|
| The Curragh | 39 | 2 | 5.1% |
| Naas | 13 | 1 | 7.7% |
| Dundalk | 7 | 1 | 14.3% |
| Gowran Park | 6 | 0 | 0% |
| Leopardstown | 5 | 2 | 40% |
| Cork | 5 | 2 | 40% |
| Tipperary | 5 | 2 | 40% |
| Navan | 5 | 0 | 0% |
| Galway | 4 | 1 | 25% |
| Fairyhouse | 2 | 1 | 50% |
| Listowel | 2 | 0 | 0% |
| Ayr | 2 | 0 | 0% |
| Limerick | 2 | 0 | 0% |
| Bellewstown | 2 | 0 | 0% |
| Killarney | 1 | 0 | 0% |
| Newmarket | 1 | 0 | 0% |
| Down Royal | 1 | 0 | 0% |