340 build

Looking at your file.....uh oh FORD ALERT! LOL.... The piston numbering is from Ford. Mopar is odd 1,3,5,7 on the driver's side and even 2,4,6,8 on the passenger side. Anyhoo...

It looks like you have some deck slope front to back on both sides (with the back higher) but you can live with that. The big variable I'll bet is that there is about .005" variation (as a guess) in rod lengths; they are probably shortest in the holes you marked 2-4. Nothing is a disaster there, just not 'blueprinted'. The average above-deck compression height number is pretty close to the standard early 340 number of .018" above deck. The piston-to-deck variation you have will give you about 1/4 point variation max in static compression ratio between highest and lowest pistons as shown, all else being equal.

The bore measurements looks pretty encouraging to me. Question: what is the meaning of the diameter 2 numbers? Top and bottom diameters? If so, that is not much taper at all. If anything, your bore diameters are too small for forged pistons.

It takes a lot of care to get accurate measurements with a telescope gauge: I do it all the time, but I take a lot of readings and have a feel for setting them. They are easy to set a bit small so your bore diameter readings may be on the small side... which would be good. (Not being critical, I just don't know how good you are at using telescope gauges....) A bore gauge at the machine shop would be nice to use and would give you accurate numbers in a trice.

And as said before, .003" to .004" is normal for forged piston clearances. They change a lot more over operating temp than cast or cast hypers.

IMHO, time to pull the pistons and check the skirts and bores, and measure the the pistons and bores more accurately. The measurement point may be on the thrust faces about 1" above the bottom of the skirts, but I have not had any TRW's in a long while so don't recall that for sure; perhaps someone here knows better, or your shop does. (It could also be measured at the pin height on the thrust faces.) It would also be time to check the rings grooves for side clearance; with 1k miles they oughta still be fine.

Did you ever look at the bottom of the heads and see if they had those shallow circular areas milled around each combustion chamber (or not)?