i'm running a 27" tire....and its a peg leg....that one wheel burnout is real impressive! lol!
best results came shifting out of first early (about 4500) and leaving the car in 2nd gear all the way to 5K or so and shifting into 3rd right before the traps.
Yeah, I run a 27" tire too, 235/70/15's to be exact. I shift at 4500 in each gear, as my cam is designed more for low end grunt. It has similar lift charactersitcs to the 340 cam, but the duration is a bit different.
What rear are you running? The stock piston will lower the compression to a very low level with the bigger valves, something like 7:3:1 without using a thinner head gasket or milling the heads. Did you pop the heads on with bigger valves, or was more machine work done to the heads/block? If you can get the compression up, you will regain some of the lost low end torque and drop the e.t. down some more.
Also, how is traction? Do you have any tire spin during the pass?