Deck height

I am going to be working toward getting a true compression ratio on my parts truck by taking the necessary measurements.

I have read that.........the stock piston compression height is 1.765

If I am reading that correctly that comes out to 1 3/4 (approx) down in the bore measuring from the top of the deck is where the piston top sits at TDC. That does not seem right. How would the engine build any compression?

I turned the parts truck engine over so that the piston is at approx TDC and as you can see the piston is maybe 1/4 down from the deck so I am confused?

Can someone clarify for me which is correct? ( approx )

225 slant, dont know the year yet of the engine, havent gotten that far yet.