The parts book is not so clear, but FROM engine7S7378 shows the senders in the familiar spot on the camshaft oil feed lines. The line comes from the left rear of the block, and splits and each end goes to a banjo fitting at the back of each head. Where the lines split, in the center of the block, there should be a casting with both senders attached, and the line connected by a banjo bolt. That is the arrangement on the 73 that I have in here now. Just where it was prior to that engine number, I have no idea. The parts book shows no alternate location that I can find. I will look harder tomorrow, as now I am intrigued.....
AHA!! If you have an early car, or it has been modified or what ever, look on the left side of the block, above the oil pan line, back near the bellhousing. The factory manual showes both switches on a "plate" in that location. I expect that on all non Etype applications ,that is where the oil filter housing bolts on.