[Humbucker]

That's not so bad for a baseline. That engine makes about 430 at the flywheel on average BEST CASE scenerio. That would equal about 325-335 or so HP at the wheels. I'd say the tune is a little off and that would account for the difference in RWHP from what you should expect.

With my new heads and intake, my RWHP hit 422. I feel pretty sure that with the new heads and a proper tune, you'll be somewhere in the neighborhood.

Here's something else... I made 8 more HP with my air filter on than when it was off. We made three pulls to verify this. It's the same air filter housing that Hal Copple uses. I forget the brand, but it' sfrom a Nascar shop in NC. It allows me to use a 3" x 14" K&N filter. Too small a filter with certainly rob some power, and with our compartment constrictions, we need to take all we can get.