I'm surprised that you are not getting higher numbers with that K27 though.
I think I will, I was really not under the best conditions and have never tried it before. I need a dead level road and the ability to start in the lane I am finishing in. Rolling on from off the side off the road can't be optimal (as my 2.7 second 60" time suggests)
For the HP #'s they don't suggest you take them from 1/4 mile run but rather, they sugggest slowly rolling through 1st gear and shifting into 2nd and dropping the hammer when you get 1/2 way to redline. So a nice normal start with a shift to 2nd at about 3400 should give higher numbers.
Even so just supposing the 309 is the best I ever do. 309 HP is net, and that is even lower than you would get on a dyno because of the wind resistance and rolling resistance of an actual run. If it were on a dyno most people add 15% to the 309 which equates to about 355 gross HP. Maybe I'm losing 18% this way and that would equal 365 gross HP. That seems about right to me. Guy who sold me the car said when the top of the engine was rebuilt 12,000 miles ago and the goodies were added it was guesstimated at 390. So who knows maybe 365-375 is more like it.
All I know is it is fast enough to SCARE out on the highway and through the turns.
The only real comparison ( that I have driven regularly) I have HP wise is my co-workers 911 C2S Tip (282 HP gross) and they are noticeably different animals. The C2S has great top end but has much less grunt and wow factor. However his car is easier to drive fast in the twisties and you can hold the cell phone in one hand and still haul a$$. Very annoying when we are driving pretty hard and he is calling me on the phone as I try to shift, brake, steer. etc.