I'd suggest doing the following Mods first:
Manifold Spacers, Cold Air Intake, Underdrive Pulley, 3.27 or 3.45 Diff, CPR6 Manifold, Headers, Throttle Controller, Larger Throttlebody & Tune from Overkill
You'd be pushing around 325 Horsepower (at best). At that point I'd look into upgrading to a 6L50 Transmission.
Last edited by Ridge60107; 10-14-2018 at 08:05 PM.