oil light on dim?

[purple gas]

So, I finally got my truck going, and actually drove it. Was shooting for June 1st. This is my first crack at one of there trucks. When you start with a shell that was dissasembled and sat for 8 yrs, with a few people "borrowing" parts from the P O, well if you been there you'll know what I mean. Anyways, I bought a 77 van with a 305 for a donor vehichle. It had guages and the oil pressure looked good when I got it. My truck has idiot lights. when the thing runs, the oil light comes on, but not real bright, barely perceptable actually.. would I be so lucky as to just have to change the sending unit, or do I maybe have a problem. Is there any way to measure oil pressure independantly form the vehichle system? Is there some handheld tool a mechanic might have?

[stelth2002]

WRONG SENDING UNIT, get a different gauge setup and put in the right sender.