600 HP
is easy enough.... Buddy has a SB Mopar with cast iron W2's, solid flat tappet, No dminator (950 HP) and runs hard.
Has Home ported W2's Crane Gold Rockers, Indy Intake. The engine is around 416-420 cubes, has some squeeze, about 13.5-14:1 Compression dyno'd at 620 ish HP on a dyno thats known to be stingy, had to slow it down to run 10 Oh class at the Classic etc in a 3000-3100 Lbs Dart, with 10" tires, leaf springs and cal tracks..
Same engine should easily run mid 10's on the Porky Challenger.
You Dont need no fancy CNC ported Indy Heads, or aluminum MP W5's etc.
There was a guy on her last month that had set of W2's cheap... Like $600..