Carb or EFI, you will make the approx same amount of HP.
EFI will help w/better all around drivability,more useable torque throughout the RPM range,but your total HP out put will be the same if you have your carb tunned correctly & correct size.
Most intakes from the factory,like the one for the Trailblzer/Envoy will have some short comings when it comes to all out HP,so in theory,if you design an intake for a carb correctly,you can make more HP than using the factory EFI manifold,which is usually designed for better low end torque & mid range for the most part,especially for a Heavy SUV like the Trailblazer..
So for HP, I would say if you design an intake for a carb or carbs you will be able to make more Top end HP over the stock set-up.
MBHD
