KB107s came in at .012 below deck in my 360. and I used a .028 gasket for a Squish of .040 on closed chamber heads.
Open chamber heads will increase this beyond mattering.
I wonder if 38*of ignition timing is putting her into detonation. It should be on the plugs.
But you seem to have that covered.
As for the bottom-end, I'd put that on the 247/247/108* cam, AND mismatched compression ratio. That's a one-two punch. At 9.9Scr and 1000ft elevation, the Wallace puts your Altitude-Corrected Dcr at just 7.21 and your cranking cylinder pressure at 143 psi, with a piss-poor VP of 113, less than a stock smoggerteen.
There is your launch problem.
Unless your TC is pooched.
IMO; you need a lil less cam, and a lot more Scr.
I'll guess one camsize, still on a 108; and 10.5Scr. That'll get you an elevation corrected Dcr of 7.94 @162psi and a halfway decent VP of 1.33
To keep the 247* cam you would need to pump the Scr to 10.8, but the VP won't keep pace so the TC better be good. That 247 cam will want to be shifted at ABOUT 6000.
All numbers are for 91 gas minimum.
Ideally, if it was mine, I'd run a solid lifter cam to pick up the pressure at low rpm.
For comparison only,
My 360 pulled 93mph@3467pounds@930ft, with a 230*cam and 3.55s; with a 2.2 or more 60ft; allbeit with OOTB Eddie heads at 10.7 Scr. She runs 72/80s in the 750DP. The altitude-corrected Dcr on mine is 8.38, and VP of 149, which spins my 325/50-15DRs for hundreds of feet. Manual trans.
