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-   -   7" vs. 9" vacuum booster for brakes...which is better? (https://67-72chevytrucks.com/vboard/showthread.php?t=408721)

67Dad 06-22-2010 05:36 PM

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

umwtnt 06-22-2010 05:50 PM

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.

mbgmike 06-22-2010 07:22 PM

Re: 7" vs. 9" vacuum booster for brakes...which is better?
 
Quote:

Originally Posted by 67Dad (Post 4043384)
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

Actually the unit that came on it was 11" in dia.
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

Musclerodz 06-22-2010 11:27 PM

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".

67Dad 06-30-2011 12:23 PM

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.

ChevLoRay 06-30-2011 02:48 PM

Re: 7" vs. 9" vacuum booster for brakes...which is better?
 
Ummm, just do it.

68gmsee 06-30-2011 09:36 PM

Re: 7" vs. 9" vacuum booster for brakes...which is better?
 
Quote:

Originally Posted by 67Dad (Post 4764412)
OK.... 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.

Go to Webster and talk to mbgmike. He'll set you up or give you good advice on what you need.

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.

1969stepside 07-01-2011 09:46 PM

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

sick69 07-02-2011 05:41 AM

Re: 7" vs. 9" vacuum booster for brakes...which is better?
 
Or to throw another twist,,,,convert to hydroboost and skip the vac booster

mcmlxix 07-02-2011 06:19 AM

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)...

http://67-72chevytrucks.com/vboard/a...1&d=1244429492

http://67-72chevytrucks.com/vboard/a...1&d=1244429543

http://67-72chevytrucks.com/vboard/a...1&d=1244429766

1969stepside 07-02-2011 10:43 PM

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

usmcchevy 07-03-2011 08:48 AM

Re: 7" vs. 9" vacuum booster for brakes...which is better?
 
Quote:

Originally Posted by sick69 (Post 4767235)
Or to throw another twist,,,,convert to hydroboost and skip the vac booster

X2, I love my hydroboost!

1970 CST Short Wide 07-03-2011 10:28 AM

Re: 7" vs. 9" vacuum booster for brakes...which is better?
 
Quote:

Originally Posted by usmcchevy (Post 4768786)
X2, I love my hydroboost!

I like to see how the hydroboost looks and works on your truck. Could you post or send me some pics

usmcchevy 07-03-2011 04:42 PM

Re: 7" vs. 9" vacuum booster for brakes...which is better?
 
Quote:

Originally Posted by 1970 CST Short Wide (Post 4768897)
I like to see how the hydroboost looks and works on your truck. Could you post or send me some pics

PM replied, Pics and some info are on pages 9, 10 and 13 of my build thread. Link in sig


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