disappointed with dyno results

[oneba87lx]

First off i'll tell you about my motor. A stock short block, f303 cam, aluminum gt-40 heads(y303), gt-40 upper and lower, 24# injectors, 65mm TB, 70mm MAF, mac equal length shorties, "cobra" MAF conversion from frpp, 1.6 roller rockers. That's my motor in a nut shell. Basically i tried to duplicate the GT-40 crate motor FRPP sells, but with a different cam. The advertisement claims 320 hp.This sounds good, but today I went to the dyno to get the real scoop.

I managed to get 243.7rwhp and 273.5rwtrq is this about right. I thought it would be higher, or maybe i'm living in a farytale.

Anyway i didn't mean to drag it out, but I would like some opinios.

Thanks