Back in 2020 like every one else I had a lot of spare time on my hands, built four different "426" combos and the advantage of owning my own 902Dyno I kept myself busy. these were all built and dyno'd in April.
1) 5.7 block, 4.00X4.25(427.257) 12.3 to 1 , HP610@6200TQ600@4800
2) 6.1 block, 4.08X4.08(426.738) 12.1 to 1 HP645@6800TQ585@5400
3) 6.1 block, 4.09X4.05(425.679) 12.2 to 1 HP640@6900TQ580@5400
4) 6.1 block ,4.165X3.9(425.084) 12.3 to 1 HP660@7000TQ570@5600(w/Darton MID sleeves)
All 4 used the same heads/cam/Intake manifold Holley 950 mech secondary carb, after each dyno session, the top end was removed and used on the next short block ,cam removed and re-degreed in each different short block.
heads, were Apache, port matched to a Prefix single plane intake, Manley stainless stock size valves, PSI 1516 spring, new valve job, spring ht and loads were all matched
Cam was .620/.640 250/260 110LSA.

All Results are an average of 10 pulls. #1 had the best BSFC ,and made peak TQ with just 18^ of timing.

I've a done a few 4.125X4.00(427.64) BGE block builds, last one was back in Sep of this year , out of the box AFR 224CC Blackhawk heads, Comp Cams 112-337-11 .635/.635 229/241@.50 117 LSA , made 660@6500 585@5000
Holley Hi-Ram with a 105mmTB its in a 2013 Challenger M6 car stock PCM(with tune)


The factory valves in the BGE, Apache and hellcat heads are very close to the bore at low lift on a 5.7 block and definitely reduce flow down low. They also cause a lot of turbulance and are probably why the TQ is higher number and lower RPM in that combo.