Guess the horsepower

I had a very similar setup in my Duster back in he 80s but with the STX 21 and a Holley Strip Dominator. It was a 4 speed street car with only a pinion snubber in the way of suspension mods. It ran 12.31 in the quarter with slicks and uncapped headers at 109 mph running 5:13 gears. It weighed 3460 with me in it. I don't know what that calculates into flywheel horsepower but I'm sure there is a formula somewhere.