68 Charger brake lines--what size do I use??

[sixpack_sid]

I am running brake lines for my 68 Charger. I bought a conv. kit to change my front drum brakes to disc. In that kit I got a prop valve and the line leading to the back of the car is 9/16 nut size. And in a separate kit that I bought the brake lines for the car, they sent me 3/8 lines all the way thru the car. So I went to the store to get some adapters for the prop valve to fit the lines and they told me the line should be thicker going to the rear. I'm confused.
Any opinions?

It appears that all the original lines are 3/8, so do I use what I have or do I go with the bigger line to the rear??

Thanks for the help!

[terrible one]

Surely you mean 3/16", right? 3/8" is huge for brake lines.

[bobs66440]

What store told you the line should be bigger? Is the line size 3/8 or the flare nut size 3/8. 3/8 line size sounds way too big. As far as I know, all the lines should be 3/16 (3/8 is the flare nut size), most cars are 3/16. 1/4" line is common to run to the rear on some applications (some GM) and on some older brake drum cars too I've read. I just put a line kit on mine from Inline Tube and it was all 3/16". It's common for there to be a different (bigger) nut size at the prop valve or master cylinder but with 3/16 line. Who did you get the conversion kit from? If they're a reputable company I would call them and see what they recommend or just go with what is OEM.

[sixpack_sid]

Surely you mean 3/16", right? 3/8" is huge for brake lines.

Yes, I meant 3/16 line, 3/8 nut size.
Thanks for correcting me.
I guess I'll run 3/16 line all the way to the rear then, and just get a bigger adapter for the prop valve.
Thanks for the help!

[terrible one]

Yep that's the ticket! If you are starting from scratch, here's an assortment of flare nuts, various sizes but all for 3/16 lines.

http://www.summitracing.com/parts/SUM-220237/