ok heres the mods that I have done to my 92 camaro with a 305tbi 170hp stock... Mods are Open element, smog pump delete, ultimate tbi mod, carb intake manifold (similiar to a performer rpm), jet chip, 170degree thermostat, hooker shorty headers with true dual no cats, no egr, 2" spacer, b&m shift kit. all just basic mods what should my horsepower be around? I'm thinking around 250 yes/no/more/less? havent run the 1/4 yet with new mods last time i ran a 15.5 with open element and jet chip still had a cat and all emissions equipment. I can feel a big difference with the new mods I'm hoping to be in the 14's what does everybody think? my rear end is still the crappy 2.73 gears with a 700r4

 

I'd say maybe 200-210 hp, low 15's. The main hurtle with the tbi is gonna be those factory swirl port heads. good for low end torque, but for any kind of decent powerband, or anything above 4000 rpm they suck. They cannot even adequately support the stock setup, let alone a modified system.

Also being that you are EFI, why not go with a good single plane manifold? You will get better flow and performance, and not sacrafice the bottom end like you would with a carb. The best of both worlds