There is NO porting of the heads allowed in T/S and the people that you see running those times (myself included) are not running ported heads. I don't know what you're weight is, but it figures significantly into the equation. I'm getting 330HP or so to the ground and have clicked off a best of 12.53@109.3 this season. Others have managed into the low 12.30's, been torn down and inspected and found to be in complete compliance with the rules. It is possible and really just comes down to working with your combo and tuning it for the maximum performance. Driving style can also be a big factor in there. I'm convinced my car will do the 30's if it had someone a little more aggressive on that stick.
Hang in there and keep working with your combo and you should see it come around.
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Jeff Chambers
T/S #4
12.53 Seconds/109.3 MPH
http://www.kellnet.com/chambers/default.htm