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#1
05-27-2026, 11:15 AM
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1968 A-body front disc conversion question.
Friends car has power 4 wheel drum that I am converting to front disc. Can I use the stock master or do I need a disc/drum master with a new proportioning valve?
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1967 Firechicken, 499", Edl heads, 262/[email protected]" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. [email protected] mph with a 1.45 60'. Still WAY under the rollbar rule. |
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#2
05-27-2026, 11:26 AM
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The master is likely fine to continue to use, however you definitely want a disc/drum combination valve.
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-Jason 1969 Pontiac Firebird |
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#3
05-27-2026, 11:44 AM
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Thanks!
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1967 Firechicken, 499", Edl heads, 262/[email protected]" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. [email protected] mph with a 1.45 60'. Still WAY under the rollbar rule. |
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#4
05-30-2026, 09:02 PM
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And if there is as Residual pressure Valve in the front it needs to be removed.
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune [email protected] 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs 1964 Corvette Coupe 327 4 speed |
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#5
05-30-2026, 10:32 PM
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What might a Residual pressure valve look like?
__________________
1967 Firechicken, 499", Edl heads, 262/[email protected]" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. [email protected] mph with a 1.45 60'. Still WAY under the rollbar rule. |
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#6
05-30-2026, 11:25 PM
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Look in the master cylinder... factory drum/drum had check valves (item 26) in the outlets. Not sure about power drum but probably the same:
Aftermarket check valves would be inline, could be anywhere. This is a typical example: |
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#7
05-31-2026, 09:10 AM
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Ive converted over by pulling the seat out of the front port where line threads in.
You can pull seat by tapping the cone shaped seat insert,thread a bolt in and yank seat With needle nose pull the rubber check valve,reinsert the seat.
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Everything comes and goes Pleasure moves on too early And trouble leaves too slow |
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#8
05-31-2026, 09:23 AM
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Good to know, thanks again.
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1967 Firechicken, 499", Edl heads, 262/[email protected]" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. [email protected] mph with a 1.45 60'. Still WAY under the rollbar rule. |
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