The seat pitch on JetStar long haul flights is 31".
Source: Jetstar - Flying with Jetstar Airways Discount fares from Jetstar the low fare airline
The norm among major carriers is 31-34".
Singapore: 32", Qantas: 31", BA: 31", United: 31", Delta: 32", SAS: 32", KLM: 32", Malaysian: 34", Thai: 33", Qatar: 32"
Source: Airline Seat Pitch