I know this is an old thread, but it seems that a tri-power set up might fit on a big block under a stock Camaro hood.
One way to find out is to measure the height of a stock Chevy bbc intake, 4-barrel carb and aircleaner and compare that to the measured height of a stock Corvette tripower intake, carbs, and air cleaner. Both measurements would need to be taken from a similar, unmovable point on both intakes, like the holes where the intake bolts pass through.