Pratt & Whitney J58 vs General-Electric J93
First of all, I'd like to clarify that the J58 that I'm talking about is not the modified bleed-bypass variants that were eventually fitted to the A-12/YF-12/SR-71, but the earlier designs which lacked it.
From what I remember reading, the Pratt & Whitney J58 was based on the J91 (which was a low pressure-ratio turbojet designed as a competitor in what would become the XB-70 program; it would ultimately lose to General Electric's J93), scaled down to 80% size for a USN high-speed high-altitude attack plane (which would ultimately emerge as the simpler A3J, powered by a pair of J79's). The projected engine thrust was to be 50% greater than that of the J75.
Okay, now here's my question. How the J58 compared to the J93 in terms of thrust?