I swapped back to 235/75/15s and got some of the low end torque back. She now likes 3000 rpms and 75mph for a cruise. It's much more drivable, but as Eddy says, it still needs some tuning. Since he drove it, I tuned a little more and have lost a little less than 1 psi - an indication that the engine is pumping better and the head work is paying off on flow.

I think I'll get another dyno session to baseline these tires, then when I have time, the first cam trial will be to roll the Diamante cams 3* forward to see if more bottom end develops. That will give me 4* more duration than OE, but with the intake valves closing at the same point as the truck cams..... which will increase the charge volume and cylinder pressure - and hopefully the power produced without adverse effect. The change should also move the torque peak a few hundred rpms lower and light up some asphalt. <img src="/forums/images/graemlins/evil.gif" alt="" />

Frank