Not a direct comparison, BUT...
The TNT 440 in the 67 Chrysler 300 was essentially a 440 Magnum. It used the same style "Magnum" manifolds with dual exhaust, the same intake, carburetor and camshaft. It also had a windage tray. The 440 "Magnum/Super Commando/TNT" was rated at 375 HP. The base 440 in the 67 Chrysler and other models used a log type exhaust manifold, a Y pipe into a single exhaust pipe and a milder cam. It was rated at 350 HP. The 25 HP difference is attributed to the cam, exhaust and windage tray. Its safe to figure that 8-10 HP could be from the exhaust system.