The larger exhaust probably won't help a stock truck until you're above 4000 rpms - it might even hurt the lower rpms.... but the only way to find out is to try it and see what happens.

At highway speeds, 1800-2000 rpms is a 3.0L dead spot with larger tires, engine loaded (uphill) and in O/D.... the A/T has to downshift to get the revs up into the curve to make enough power to accelerate. That's one reason I've swapped to a later transmission... the '91-'94 A/Ts have a lockup torque converter with a more favorable final ratio which should increase O/D rpms by about 200 at highway cruise - without the slippage allowed by the non-lockup models to get the engine in the power band. I'm hoping that the extra rpms will keep the truck nearer the sweet spot and I can then depend on the extra power from boost to get the truck to accelerate under load on the highway..... at least that's the plan. <img src="/forums/images/graemlins/wink.gif" alt="" /> Time will tell.

Frank