LA360 compression

KB107s should drop in at around .012 below deck of an LA
I think something is wrong
IMO, you need to get your combo up to at least 9.8.
at a bore of 4.03, that would be 85cc@sealevel. It doesn't much matter how you do it.

But I just don't see how KB107s can be .100 down, that should be impossible.
My KB107s measured 1.675 on the nose and everyone exactly the same.
My guess is that if you had the crank reground then she ain't no 3.58 stroke any more. But if the crank is ok, then the stinking rods are short, by a whole big bunch.
Kb makes pistons with raised Q-pads for open-chamber heads. KB 190/191s

I know yur gonna hate me, but IMO, I would back up the bus. I would NOT assemble it with the parts you have, unless yur running an exceptionally light car, an exceptionally high stall, or exceptionally deep race gears, or just don't much care about low-rpm power. Otherwise, the bottom end is gonna be exceptionally boring.
_____________________________
Here's what I know works, cuz I built it
KB107s at ~ plus .005 above deck = 4cc
closed-chamber alloy heads @63cc
FelPro 1008s at .039" =8.6cc
The total chamber volume was thus 75.6cc
the bore was 4.045=753.9cc of swept
The Scr thus was 10.97
A cam with an Ica of 61*.
At sealevel, this calculates to a Dcr of 8.99 and a predicted Cylinder pressure of 190.34psi
The Q was .034
I ran this on 87E10 at 930 feet elevation at 34* of power-timing and at 3650 pounds, for 4 years Car went 106mph on it's only run; with 3.55s, 245 street tires, and a 4-speed.
Oh yeah, and it got phenomenal fuel economy. This was my DD at that time.
Had my Scr been 8/1
The pressure is predicted to have been 126psi, and this combo at low rpm would have felt like a 2bbl 273