Hello,

I have a 71 Chevelle with a inline 6 inside. I'm looking to convert my front drum brakes to disc brakes. I found on SS396.com a great deal on a 1964-1972 Chevelle Front Disc Brake Conversion Kit:

http://www.ss396.com/chevelle_parts/chevelle_disc_brake_kit.htm

My question is regarding the booster size. The site offers a 9 or an 11 Inch booster size. Which one I need to buy? With my engine size, the space is not an issue to put the biggest one. But did it a vaccum question or something like that?

Thanks for your answer,
Mino71

11" will give you much less pedal effort for power brakes than a single diaphragm 9". Assuming your vacuum provided by the motor is up to par. The smaller boosters are typically used where there are space/fitment restrictions. I'd go 11" if I were you.

14-16" of vacuum minimum 22"+ recommended for the 11" booster, more vacuum req. the smaller diameter booster you go.

Thx for your answer guys, for now my stock L6 250 produce probably enough vaccum to connect a 11" booster. But If one day I wanna change my engine to a real one, 350 or 396, did the 11" booster will fit on it? A friend told me that a modified engine produce less vaccum then a stock one.

I just wanna be sure to buy something that I will not regret after.

Chris

But If one day I wanna change my engine to a real one, 350 or 396, did the 11" booster will fit on it? A friend told me that a modified engine produce less vaccum then a stock one.


This is true, Chris. Although you can build an engine AND have good vacuum and street manners. When you get to the point where you are going to build a performance engine, you need to talk it over with your builder and specify how much vacuum you will need. He should be able to spec a camshaft for you that will perform.

[QUOTE=GenPac;2760985]14-16" of vacuum minimum 22"+ recommended for the 11" booster, more vacuum req. the smaller diameter booster you go.[/QUOTE

Not to hi-jack this post, but i'm in this debate with myself right now...

Just to be sure...the smaller the booster the more vacuum will be needed??

My big reason is that I prefer the looks of the 9" Delco style booster better, but better stopping will definatly trump looks...