Alignment, tire pressures, dragging brakes, even bearing issues can cause drifting. The PS valve adjustment usually will not cause much of a pull to one side
while driving, unless it it waaaay off. Start by verifying tire pressures first, and make sure all 4 tires have the same amount of wear on them, as best you can.
Raise the front end/tires off the ground, with the wheels straight, and start the car. Do NOT reach in between the spokes of the steering wheel to do this!! Sit in the car to start it, but do not hold the steering wheel. If the PS valve is off, it can whip the wheel to one side HARD, and will hurt you!
If the wheels move slowly to one side or the other, then the valve does need a minor adjustment. If they whip hard, then it needs a large adjustment. If they don't move at all, the valve is properly adjusted, and this is not causing your drift issue.
From there, it's alignment time. You will need to find a shop that is familiar with '63-'82 Corvette alignment procedures, and has the equipment to do it. Any alignment on these cars require front AND rear be done. Just setting the toe on the front ain't gunna cut it.
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Joel Adams
C3VR Lifetime Member #56
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