New engine issues
OK, 526's per the spec sheet photo provided would standard aftermarket 318 pistons. Compression height is indeed 1.74" or very close to that. The 9:1 reference in that catalog listing is not the actual you will get in a standard block; that is just the marketing number Mopar used. Real SCR of these in a standard block is 8:1, + or - with the typical LA heads.
Thanks for the pix.... but that last pix is not of 526P pistons tops... Dunno what they are; those swirly shadows sure are funky and look like some sort of reliefs. Are you sure this is your engine or has someone been messing with your camera? LOL Looks like some crazy Toyota piston top.
With those, I can maybe see the highest areas being almost level with the block. But with what look to be some sort of swirly dishes in the piston tops, that are fairly deep (like .050" deep), those will lower the CR back down some. I sure would like to find out what those pistons are....
Is this a later 318 block?