WTB Proportioning Valve

[340_RR]

Hello guys. Does anyone happen to have a spare proportioning valve that'll work on a 1973 Roadrunner with a 340? Preferably something used oem/NOS. Thanks!

 

[68plymouth383]

I have a good used 1 available. 150 shipped in the Us.

 

[340_RR]

I'm still learning this stuff but someone told me since the roadrunner has 4 corner drums, my unit is a distribution block and not a proportioning valve. Is your unit a distribution block? Thanks!

 

[68plymouth383]

Mine was from a disc/drum car. It's a prop Valve. I do have distribution blocks as well from drum/drum cars.

 

[340_RR]

Okay great. I'll PM you

 

[s/w theo]

This is the only one I could find in my stash.

 

[340_RR]

"RI" stands for Rear Inlet....."RO" stands for Rear Outlet.... "FI" stands for Front Inlet.... "FO" stands for Front Outlet... and "BS" stands for Battery Switch.

Is this the right setup?

 

[s/w theo]

I do believe you are correct.

 

[340_RR]

Kern Dog said this in FABO. I don't know if it would be a bad idea to put a distribution block on a disc/drum car like the one you have. Not too familiar with this stuff, learning a lot.

 

[Sixpactogo]

I'm still learning this stuff but someone told me since the roadrunner has 4 corner drums, my unit is a distribution block and not a proportioning valve. Is your unit a distribution block? Thanks!

Did that someone that told you that, know for sure you have drum brakes? Seems to me by 1973, front discs were more the norm.
First thing you need to do is verify. Shouldn't take more than a minute of your time.

 

[s/w theo]

Kern Dog said this in FABO. I don't know if it would be a bad idea to put a distribution block on a disc/drum car like the one you have. Not too familiar with this stuff, learning a lot.

View attachment 1683108

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I'm not positive about this either. I thought the main difference was the master cylinder.

 

[Sixpactogo]

I'm not positive about this either. I thought the main difference was the master cylinder.

The main difference between a distribution block and proportioning valve is the distribution block sends the same pressure to the rear brakes as to the front brakes. Since front disc brakes require about twice as much pressure, you need a proportioning valve that has a smaller orifice for the rear brakes, reducing the pressure to the rear brakes so they don't lock up. The Master cylinder could care less whether you have discs or drums.

 

[340_RR]

My apologies for not updating. I went out yesterday and checked and I have discs up front.

 

[340_RR]

The main difference between a distribution block and proportioning valve is the distribution block sends the same pressure to the rear brakes as to the front brakes. Since front disc brakes require about twice as much pressure, you need a proportioning valve that has a smaller orifice for the rear brakes, reducing the pressure to the rear brakes so they don't lock up. The Master cylinder could care less whether you have discs or drums.

Thank you for clearing that up. I will rebuild the proportioning valve that I have and will let you guys know if I have any other troubles along the way.

 

[Sixpactogo]

Thank you for clearing that up. I will rebuild the proportioning valve that I have and will let you guys know if I have any other troubles along the way.

Good luck with your rebuild. There is not much to them and pretty easy.

 

[340_RR]

Good luck with your rebuild. There is not much to them and pretty easy.

Thank you very much. It seems to be a pretty straightforward piece.

 

[340_RR]

I'm not positive about this either. I thought the main difference was the master cylinder.

Sent you a PM theo

 

[s/w theo]

These are pix of the electronic ignition system I have for a small block. It was all in one box & easy for me to get to. The other things I have, will take some rooting around to find all of it, mostly Mopar brackets & stuff like that. Let me know what you would be interested in & I'll know if I have it, I just have to find it.