Heck, no, you should be able to buy one off the shelf at someplace like Auto Zone, although (1) my local preference is Lee Auto, if you have them in your area, because they stock AC-Delco parts, and (2) I would at least lay eyes on the existing sending unit before going off to buy parts, because if the current one is clean and dry on the outside, I would definitely spend some bucks on a mechanical oil pressure gauge instead, not a sending unit.

See, they're about the same price anyway (I think Wal-Mart charges only about $10 for a mechanical gauge), you're going to have to remove the existing sending unit temporarily regardless, but if the current one isn't leaking, I'm afraid you've got a real oil-pressure problem.

You will need the gauge to confirm this anyway, and afterwards you will have the gauge to put on the shelf for future use next time.

If you buy another sending unit first, all you will have at this point is an extra sending unit, which has just proven that there was nothing wrong with the first sending unit. :-) So I vote for buying a mechanical gauge first, because it will definitely tell you what you will need to do next.

And besides, if you take it to the shop, if they're competent, _they're_ going to put a gauge on it to see what's up.

My sending unit was reading high. That's when I decided to replace it. I did it by taking off the passenger front wheel and splash guard. Easy access there.

A Series II engine might be different.