Get a good sound clip, and I can tell you what is going on, whether it is too rich or too lean... It took me a long time to get the "Tuners Ear" but once you have it, you will never lose it.... Did you listen/watch the vid of my truck I posted today? Could you tell it was running too rich? Hee Hee It is hard to tell (especially with my crappy video/audio) but it can be heard... But, from what I have learned in this hobby (large scale) if it has a pipe and doesn't pull the front wheels, it is too lean... The throttle response shouldn't make a difference whether you are on pavement or snow... It should sound the same when you punch the throttle... An, Instant "Snap" if it doesn't, it is probably too lean!
I just hope your ported 27 is what you wanted/expected it to be...
Trip..