All chassis dynos are simple tools. And not as good as an engine dyno at giving comparable numbers. Using the formulas I've always used (and everyone has an opinion on what is "right" or not...) I come out with 378 crankshaft hp, and 438 pound feet tq. The factory rating was 335, and realisitcally the factory floor engines made about 300. On a chassis dyno similar to yours, that's about 268 to the tire. For a true 9.5:1 (which BTW us not easy to get due to piston choices...), a cam with 240°@.050 and .507 lift (.338x1.5) is huge. The exh manifolds are the factory log type, you are giving up a bunch of hp an torque. If the intake is a dual plane M1, you're giving up some hp and tq. If it's a single plane, you're giving up more hp and tq than the M1 dual. In any event, if you were to get a true 10.2:1, and run HP manifolds, plus and RPM intake, I'd think it would be much closer to 350 to the tire. Just my thoughts. So what intake and exh manifolds are you running? What piston was used?