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#1 |
Registered User
Join Date: Mar 2010
Location: houston texas
Posts: 84
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7" vs. 9" vacuum booster for brakes...which is better?
67-c10...we are adding power brakes. Apparently the conversion can be either 7" or 9". Do any of you have experience with which is best? 7" presumably leaves more engine access room, but we have a straight 6 292. Does 9" give much more "boost"? Thanks in advance!
Mark
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Mark 57 Austin Healey 3000 (sold many moons ago, unfortunately) 67 C10 (in progress, son's) w/ 1993 350 SBC, '96 Vortec heads (custom polished ports), EPS Performer intake, Holley carb, cam, MSD ignition 93 C4 Corvette (mostly done, son's) |
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#2 |
Registered User
![]() Join Date: Feb 2008
Location: Williamsburg, Va
Posts: 226
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Re: 7" vs. 9" vacuum booster for brakes...which is better?
A 9inch booster is better. Its simple physics, the 9 inch has more sq in for the vacuum to act upon the the 7 inch. This helps apply more force with less pedal pressure. You have the room you can go to a bigger booster if their available.
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The more I learn, the more I find out I don't know. 69 Chevy SWB w/67 front end 4 wheel discs 468 BB 700R4 Bagged Coming around slowly |
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#3 | |
Registered User
Join Date: Aug 2005
Location: Pasadena,Tx /Pto Pta DR
Posts: 5,415
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Re: 7" vs. 9" vacuum booster for brakes...which is better?
Quote:
You have more boost. Sometimes they use a dual diaphragm booster in the smaller sizes to gain more room. If you have any questions feel free to call or drop buy we have done a lot of conversions. Mike |
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#4 |
Senior Member
Join Date: Aug 2005
Location: OKC, OK
Posts: 2,365
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Re: 7" vs. 9" vacuum booster for brakes...which is better?
Either run a factory 11" or dual 9". Don't bother with single diaphragm boosters less than 11".
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Mike Redpath |
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#5 |
Registered User
Join Date: Mar 2010
Location: houston texas
Posts: 84
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Re: 7" vs. 9" vacuum booster for brakes...which is better?
OK...we are back on the brake project after many diversions. Any opinions out there as to the best all around solution to adding power brakes (w/ new master cylinder in the process) to what was a manual brake 67 C10?
Thanks.
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Mark 57 Austin Healey 3000 (sold many moons ago, unfortunately) 67 C10 (in progress, son's) w/ 1993 350 SBC, '96 Vortec heads (custom polished ports), EPS Performer intake, Holley carb, cam, MSD ignition 93 C4 Corvette (mostly done, son's) |
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#6 |
Old Skool Club
![]() Join Date: Jun 2001
Location: Benton, AR "The Heart of Arkansas"
Posts: 10,880
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Re: 7" vs. 9" vacuum booster for brakes...which is better?
Ummm, just do it.
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Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was. |
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#7 | |
Active Member
![]() Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
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Re: 7" vs. 9" vacuum booster for brakes...which is better?
Quote:
Otherwise if you have a salvage yard that has some 67-72 trucks find one with the power brakes and take everything off that pertains to the p.brakes: mounting bracket, master cylinder, prop valve and include the brake pushrod inside the cab. The rubber hose and check valve you can get at local parts stores and if the booster is defective you'll have the core. |
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#8 |
Registered User
Join Date: Feb 2008
Location: Johnson City Tennessee
Posts: 1,187
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Re: 7" vs. 9" vacuum booster for brakes...which is better?
what i would do is to take a power booster off a 3/4 ton and put it on a half ton because the 3/4 ton booster is desgined to stop a heavier truck and the half ton is lighter and then u can have alot of brakes lol that is what i would do just go to autozone and order u a 3/4 power booster and use ur 1/2 ton booster as a core
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Greater love hath no man than to lay down his life for a friend. Members i Have met Earl Slick68 1969 Stepside Build thread http://67-72chevytrucks.com/vboard/s...=1#post4253546 ![]() ![]() |
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#9 |
Registered User
Join Date: Sep 2006
Location: colorado springs colorado
Posts: 737
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Re: 7" vs. 9" vacuum booster for brakes...which is better?
Or to throw another twist,,,,convert to hydroboost and skip the vac booster
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70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub |
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#10 |
Collector of Projects
Join Date: Apr 2003
Location: Las Vegas
Posts: 3,106
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Re: 7" vs. 9" vacuum booster for brakes...which is better?
Either way get a booster bracket from CaptainFab... it allows you to use the late model 1988-1998 full size truck/Tahoe/Burb booster (smaller, less expensive, can be found at any parts store) unless your going for stock resto... The only thing to check is column shift clearance. Click HERE
You can also use this for hydroboost if you want to upgrade (now or later)... |
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#11 |
Registered User
Join Date: Feb 2008
Location: Johnson City Tennessee
Posts: 1,187
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Re: 7" vs. 9" vacuum booster for brakes...which is better?
i like how that bracket is smaller and does not stick out as much as the stock one
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Greater love hath no man than to lay down his life for a friend. Members i Have met Earl Slick68 1969 Stepside Build thread http://67-72chevytrucks.com/vboard/s...=1#post4253546 ![]() ![]() |
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#12 |
Has more rust than truck...
Join Date: Apr 2005
Location: Ivanhoe, MN
Posts: 2,421
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Re: 7" vs. 9" vacuum booster for brakes...which is better?
X2, I love my hydroboost!
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#13 |
Senior Moment
![]() Join Date: Mar 2002
Location: Pittsburg Ca
Posts: 4,138
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Re: 7" vs. 9" vacuum booster for brakes...which is better?
I like to see how the hydroboost looks and works on your truck. Could you post or send me some pics
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1970 CST LS 1 6 speed Ford 9 inch Detroit Tru Track, Dakota Didgital, Vintage Air, QA1 Coil Overs Front & Rear Lots of FUN 2013 GMC PU, Oldest Son 71 GMC LWB. QA1 Suspension, Angry SB. Youngest Son 2019 GMC Diesil Dually. Youngest Son 2017 Toyota SUV Daughters car 2018 Traverse , Wife’s Ride Pittsburg Ca 94565 |
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#14 |
Has more rust than truck...
Join Date: Apr 2005
Location: Ivanhoe, MN
Posts: 2,421
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Re: 7" vs. 9" vacuum booster for brakes...which is better?
PM replied, Pics and some info are on pages 9, 10 and 13 of my build thread. Link in sig
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brake booster, power brakes |
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