min clearance for headers and PS pump

Power steering pump is fastened to the engine. The headers & the pump won't move relative to each other when the engine moves. Do you mean the steering box? The left side of the motor will lift & the motor will move away from the steering box when the motor revs. Torque strap is a good idea though.
Yes, I did mean the ps box, I just looked at some straps and they look like a good idea. Thanks to both above.