Choosing piston

[Idaho]

Icon 745 is for LA block. 744 is magnum block, a little less pin height.
Here's a build from Brian IMM engines with all the info for 10.2 static
Small-Block Mopar Stroker Dyno Test - Car Craft Magazine - Hot Rod

I looked at that quite some time ago. This is almost my exact setup. Same heads (LA version), intake, carb, headers (mine are Dougs version).
The difference is his cam is bigger than I'm planning. He used the XE 295 HL hydraulic flat tappet. .564/.564, .251 int .257 ex 110 LSA.
I will likely use the Thumpr which Brian has shown to make good power in a similar combo (can't recall the numbers).
The version I'm looking at (283HR7) is .513/.498, .227 int .241 ex 107 LSA.
I imagine the XE cam with longer intake duration will bleed compression down a bit.
Roller version may have a more aggressive lobe, not sure. I'm guessing a bit more torque, less HP.

 

[Krooser]

"Exact" is like within .006 lol. Jk
Compression height/pin height.
And that's based on a rod length being blue printed, a stroke blue printed, and an OEM deck height being blueprinted.... aka perfect.

There is always a hair variable.
So the rod is .002 shorter.... and the deck is taller by .008..max and .003 at the small end.. but the machinist just squared it and took .007 at one end and .002 at the other.. and the mains were line honed... etc... it's a stacking of clearances

The reason you go to a competent shop is to eliminate those stacked clearances. You rebuild the rods (or redo those import rods) so each one is spot on. Both decks get squared and cut the same. You check the pistons to be sure the pit height is the same in every one. You must check valve run-out on every valve not just assume they are good to go in those shiny new heads or the "just rebuilt" factory heads from eBay.