[He only drives it ultra-conservative since it only has stock rods in it, so you wont be able to use any ET he has run as a gauge for power output.
Here are Tlowes dyno results.
1st run 235 hp @ 4550 rpm torq was above 300 from 2700-4700 rpm. max tq was 320
2nd run 243 hp with 1 more degree of timing 26 total
3 rd run 240hp @ 27 degrees timing.
Kinda hard to guestimate 450 HP w/those results .

Maybe there are unpublished 450 HP dyno results?

MBHD