[355s10]

hey i have a 350 in my 87' s10 with a .502/.510 hyd. roller cam, and i just drove it around the shop yesterday and noticed the brakes didn't have much vacuum, could this be because of the cam? is there anythign i can do to get more vacuum?

 

[jeff79]

Need more info

yes that is a healthy cam but what intake do you have and what heads with port sizes and such.... if you are running a single plane intake and healthy breathing heads then you may be suffering from low vacume and the brakes may be suffering from this..... I would first verify that you have no vacume leaks and that the booster is holding vacume..... If everything is good then you need to hook up a vacume gauge and find out how much vacume you are producing from the intake.... You may need to buy a vacume resivore to hold vacume...

 

[eloc431962]

Yes there are ways to get more vacum, but first you need to do what jeff said and check those things out first, check and see how much vacum you have now power brake booster needs 14-16 inches of vacum to run the power brakes properly or in most cases. Some people will disagree i am sure. JMO Cole

 

[355s10]

its a dual plane high rise edelbrock performer rpm and they are edelbrock aluminum performer rpm heads 2.02 1.60 and i think 64cc but i'm not positive about that. yah when i pull the vacum plug out it makes a pop so that shoudl mean that the booster works right? i switched from the single plane booster to the dual plane( thicker but less diameter) because it was too close to my valve covers. how do i check my vacuum pressure?

 

[techinspector1]

Some people will disagree i am sure. JMO Cole

In my experience, it takes 18" hg to operate 'em PROPERLY. You can stop the car with 14-16, but not as easily as you can with 18.

Use 14-16 degrees initial ignition timing at the crank and tailor your centrifugal advance in the distributor to limit total advance (initial + centrifugal) to 36 degrees or a little less.

Advance the camshaft 2-4 degrees.

There is vacuum and there is pressure. There is no vacuum pressure. Manifold vacuum is measured in inches of mercury (in. hg). On the front of the carb are two vacuum ports. The bottom one is manifold vacuum. Connect a rubber line to that port and the other end to a vacuum gauge. Read the gauge.