If you file down the throttle stop you can increase the amount of air getting to the engine and more hp. I think the factory is at about 20degs. You can reduces it almost strait 5degs so that if there's a broken throttle it should steal close.
The 69 Firebird and the 69 GTO had the same Ram Air 3 engine. But the Firebird had a restricted throttle. Because they didn't want the Firebird to have the same hp as there flagship GTO.

 

Hmmmm, they must have a "special" TB on the Camaro. The throttle blade on my LT1 Vette is darn near straight across when it hits the stop. What's also important is that the throttle blade opens up all the way when the gas pedal hits the floor, check that too with the help of an assistant. What do you mean by "a broken throttle", if the cable breaks? The spring will still snap it back shut.

 

My camaro's tb goes straight across when wide open too. Not sure where OP got his info

 

If the throttle spring brakes.

 

I was curious myself and I checked the motor I have sitting on my engine stand and that throttle goes wide open and that thing has a 150K on it. I thought it was a little odd the Lt1 has been out for over 20 years and we just found a very basic design defect. I know the stock throttle body is not hurting the HP because guys that install larger aftermarket TB on stock motor gain little to no HP. Once you start porting and polishing then the TB can hold you back.

 

Well it is a different story with the LS1… http://www.bowlingss.com/Mods/Instal...Stop%20Mod.mht