Heres what I starded with so you can get an Idea of how much was cut on mine. The bottom of it goes all the way to the firewall.
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1996 Trans Am, Chrome C5 wheels, 350 gen 1 sbc,World Sportsman II heads, Summit 1.5 RR's, Lunati Cam, Edelbrock intake, Holley Carb, Walbro 255 lphFuel Pump, T5, Spec stage 2, Mac mids & Y pipe...
http://www.youtube.com/watch?v=LuFX9dgRAAo