I have a 68 chevelle with power drum brakes. I want to switch to front disks. I was wondering if i can use my pwr booster from my drums. Also what master cylinder will i need. I was told i need a 1 1/8bore one. Now the most confusing thing to me. I have what i understand is a distubution block down below the master on the frame rail, is this right? With the new discs in front do i need to use that or not? Where does the proportioning valve go? I was looking at putting a prop/ comb valve that mounts right next to the master cylinder on. If i do that can i leave the distibution block down on the frame? Heres a pic of the prop/combo valve i want to use.
http://cgi.ebay.com/ebaymotors/DISC-DRUM-PROPORTIONING-VALVE-WITH-LINES-BRACKETS_W0QQcmdZViewItemQQcategoryZ34199QQitemZ45 94576501QQrdZ1#ebayphotohosting

I have a 68 chevelle with power drum brakes. I want to switch to front disks. I was wondering if i can use my pwr booster from my drums. YES

Also what master cylinder will i need. Get one for a 70-72 with front discs you will also need to change the push rod to the shorter version.

I was told i need a 1 1/8bore one.

Now the most confusing thing to me. I have what i understand is a distubution block down below the master on the frame rail, is this right? YES

With the new discs in front do i need to use that or not? If you use just a proprtioning valve(small round mountedby master cylinder) yes

Where does the proportioning valve go? Depending on the one you get either by the master cylinder or on the frame.

I was looking at putting a prop/ comb valve that mounts right next to the master cylinder on. If i do that can i leave the distibution block down on the frame? Heres a pic of the prop/combo valve i want to use.
http://cgi.ebay.com/ebaymotors/DISC-DRUM-PROPORTIONING-VALVE-WITH-LINES-BRACKETS_W0QQcmdZViewItemQQcategoryZ34199QQitemZ45 94576501QQrdZ1#ebayphotohosting

That is a combination valve that is still available from GMpartsdirect. That particular one mounts on the frame. If you decide to use that one and frame mount it your will need to do a little, and I mean alittle, brake line modification. The brake light terminal on the top also is different and you'll need to change the terminal on your factory wire to adapt to it. You will also need the frame brackets for the disc drum hoses as they differ from the power drum brackets OR you can use front brake hoses from a 69 camaro and they do fit the drum bracket hose frame brackets. Good Luck Pete

So it sounds like i would be better off keeping the distribution block and using the prop valve by the master like it came stock on disc cars in that yr. Is there any proformance diffence between the old still prop valve and the new combo valve? How and where do i get the shorter pushrod?
Thanks,

So it sounds like i would be better off keeping the distribution block and using the prop valve by the master like it came stock on disc cars in that yr. Is there any proformance diffence between the old still prop valve and the new combo valve? No

How and where do i get the shorter pushrod? Baer Brakes
Master Cylinder Pushrod Extension

Thanks,

Hope that helps. Pete

So it sounds like i would be better off keeping the distribution block and using the prop valve by the master like it came stock on disc cars in that yr.
If you want to trick it out a bit, you can eliminate the junction block by putting an aftermarket prop valve on the frame (i.e. in the same location as the junction block). Many prop valves have two outlets for the front brakes and a brake failure switch, so they can function both as a prop valve and a junction block. That way you can eliminate the (in my opinion) ugly bracket and prop valve setup on the booster. I wish I had thought of that when I was converting my -69, it wouldn't really have been much more difficult to do it that way.

I have pwr drum brakes on my 68 and i have the distribution block by the frame and what i think is a proportioning valve by the master cylinder. Would this be right for a 68 all drum brake car?

There are pics of mine in this thread:

http://www.chevelles.com/forums/showthread.php?t=94360&highlight=disc

I ordered my booster push rod from Master Power Brakes.

I have pwr drum brakes on my 68 and i have the distribution block by the frame and what i think is a proportioning valve by the master cylinder. Would this be right for a 68 all drum brake car?

Lucky3,
I have a 69 all-drum brake car, and it just has the junction block on the frame. There is no need for a proportioning valve when there are no disc brakes in the equation. The purpose of a proprtioning valve is to supply different amounts of pressure to your discs vs. drums, since they differ in their pressure requirements to stop the vehicle. Disc brakes require much more pressure to "squeeze" pads on rotors, than drums do to "push" shoes out to the drums.
therefore, if I remember correctly, it's somewhere around a 70/30 pressure split, give or take, depending on the vehicle.
hope that helps!
-Gambi69