not sure what this is for my brakes
 

i am redoing my brakes and i put the new master cylinder in and went to replace my hard lines and with a zip tie this was with it
http://i114.photobucket.com/albums/n...-28-10_752.jpg
http://i114.photobucket.com/albums/n...e/IMG_5004.jpg

can someone tell me what this is so i can replace it. or do i need it? thank you :)

i did a random search and found that its a Proportioning valve. but on my chevelle i have this
http://www.chevelles.com/showroom/da...e_location.jpg
so do i need the part on the tom?

I can't remember what it is called but it is part of the braking system and it goes up by the booster. Mine has one on it as well.

Yes, that IS the Prop Valve and is needed on a disc brake system unless you've installed an adjustable proportioning valve somewhere else on the vehicle.
The brass thingy on the frame is just a Distribution Block.

That valve was only used on 69 and 70. The 70 also had a brass valve in the back on the frame by the rear wheel to hold pressure to the rear brakes. The distribution block you have on your frame does not look stock to me so you may not need the proportioning valve by the brake booster. If you use a distribution block for a 71 or 72 you do not need proportioning valve at all. Here's how the stock set up looks.

http://i777.photobucket.com/albums/y...lle/Wiring.jpg

that was just a random picture i found its not mine. the one in your picture looks like mine.
think this will work?

http://www.summitracing.com/parts/rsd-pv68