keeping the gearbox has alrerady limited your options, to the 2.6.... unless you wanted to adapt some other motor
starion/conquest 2.6 is a strong fun motor, that responds well to basic upgrade/mods.... still on stock internals
Even 300hp / 300tq will be a blast. TBI 2.6 has touched 400 hp and 400 tq. Impressive power for what it is