Originally, the Blackbird's J58 engines were started with the assistance of two Buick Wildcat V8 internal combustion engines, externally mounted on a vehicle referred to as an AG330 "start cart".
Inițial, motoarele J58 ale Blackbird erau pornite cu ajutorul a două motoare cu ardere internă de tip Buik Wildcat V8, montate la exteriorul unui vehicul, numit AG330 “start cart” (cart de pornire).