what are the difference of these two units and which one would use and why?

My oil gauge reads low on right after starting when its cold and takes a while to move up. I just change the oil and did the same thing the followng morning, so I tried not accelerate and gradually speed up, is this normal ? Anyone can explain. I appreciate any feed back.

Can someone point me in a direction to figure this out. OK the car ran fine until I had to replace the intake manifold I went ahead and rebuilt the throttle body, replaced the steering gear box, thermostat and belts. Also replaced the the valve cover gasket.. NOW. I can't get it to start. It's driving me nuts. What am I missing? This is my first project car that I am trying to do by myself. Any suggestions would be appreciated!

whats the code number for the starquest?