Guess the horsepower

flipper said
Bought this , won't be able to run it til next summer , take a guess at horsepower just for fun
340 bored .020" over
10.5:1 speed pro hyperutectic pistons
Racer brown solid cam, .520 lift, can't remember duration but it's a lot
360 j heads fitted with 2.02/1.60 valves, ported and flow tested (255 from on intake)
Titanium retainers
Victor jr intake
273 rockers (adjustable)
Windage tray
I think the crank is turned .020" on both mains and rods

Your Cam is ST-21. .520 lift on intake and exhaust with 286 duration- direct connection in 1978 catalog. I use this cam in my build back then with Torker intake,273 rockers, 750 cfm Holley, 4 speed transmission with 410 post end. Ran in mid 13's all day. But then in the 70's, was not bad. This was a street car. For Horse Power- around 450.