70 C20 disc conversion questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Beecee336 · 10-19-2023, 08:15 AM

I've read through a bunch of threads but haven't found the answer I'm looking for.
I'm just finishing up the POL 8 lug disc conversion on my 70 longhorn c20. I got a new 73-87 M/C and PV2 prop. valve. I know the rear reservoir of the M/C goes to the front of the prop. valve for the front discs. the original front drum brake plumbing was 1/4" line from distribution block down to T on crossmember then 3/16" lines out to the A arm flex line connection. the new prop. valve has (2) 3/16" line ports for the front brakes.

My question is, will (1) 3/16" line from new Prop. valve down to T at cross member be sufficient to feed both calipers? or should I run (2) new 3/16" line all the way from the prop. valve to each caliper or can I cap 1 port and just use the 1 lower 3/16" port to feed both front brakes?

any help and knowledge is much appreciated

**67 twins** · 10-19-2023, 09:10 AM

Yes. You can cap one & just use one port to feed the T fitting.

**Sheepdip** · 10-19-2023, 10:11 AM

Twins is correct

Beecee336 · 10-19-2023, 10:21 AM

Thanks for the replies. that's good news as I already ran that line before I questioned it.

10-19-2023, 08:15 AM	#1
Beecee336 Registered User Join Date: Mar 2022 Location: Broomfield, Colorado Posts: 29	70 C20 disc conversion questions I've read through a bunch of threads but haven't found the answer I'm looking for. I'm just finishing up the POL 8 lug disc conversion on my 70 longhorn c20. I got a new 73-87 M/C and PV2 prop. valve. I know the rear reservoir of the M/C goes to the front of the prop. valve for the front discs. the original front drum brake plumbing was 1/4" line from distribution block down to T on crossmember then 3/16" lines out to the A arm flex line connection. the new prop. valve has (2) 3/16" line ports for the front brakes. My question is, will (1) 3/16" line from new Prop. valve down to T at cross member be sufficient to feed both calipers? or should I run (2) new 3/16" line all the way from the prop. valve to each caliper or can I cap 1 port and just use the 1 lower 3/16" port to feed both front brakes? any help and knowledge is much appreciated

10-19-2023, 09:10 AM	#2
67 twins Senior Member Join Date: Mar 2019 Location: Herculaneum MO (20 minutes south of St. Louis Posts: 756	Re: 70 C20 disc conversion questions Yes. You can cap one & just use one port to feed the T fitting. __________________ 67 C10 283 T5 swapped longbed fleetside = wife's daily driver(divorced) 67 C20 292 (originally a 250)4speed longbed fleetside w/original wooden bed=my project truck 67 C10 283+.060 (so a 292 as well)T5 swapped longbed fleetside=my DD(Sold) 72 C1500 Sierra Grande 350 TH350 longbed fleetside=wife's fair weather truck(divorced) 73 El Camino SS 454 4 speed my first big block Can you tell we are fans of longbed fleetsides & 67s Chris

10-19-2023, 10:11 AM	#3
Sheepdip Senior Member Join Date: Nov 2018 Location: Waterford California Posts: 2,893	Re: 70 C20 disc conversion questions Twins is correct Attached Images

10-19-2023, 10:21 AM	#4
Beecee336 Registered User Join Date: Mar 2022 Location: Broomfield, Colorado Posts: 29	Re: 70 C20 disc conversion questions Thanks for the replies. that's good news as I already ran that line before I questioned it.



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