I've seen stated several times (though I don't know how accurately) that at one point it was intended that the A-11/YF-12/SR-71 would burn boron hydride fuel (like the XB-70 was planned to do...)
Given the leakiness of the tanks and the pyrophoric nature of boranes I think the results would have been interesting to say the least! Dumping heat into a borane could only result in one thing