Thats because thier idiots. Every other engine they have build recieved aftermarket pistons for a compression boost. They left the stock replacements in and instead of spending $300 on KB hyper flat tops they wasted a pile of money on eddie heads,harland sharp rocker etc etc. That poor 360 made 372 h.p with 8:1 compression or close to it. With the right piston Im sure power would have exceeded 425 h.p by a fair margin.In spite of this the engine still made about 430 ft/lb's of torque!
Not thier first engine build so they have no excuse.
Send those morons an email.I did.