cam specs at .050 240/246 .3390/3410
when decellign from 5 grand my brakes are fine but when im at lower rpms and coasting up to a stop sign i can barley get my car stoped i have to use all my leg stregth to get the car stoped.... is it because of the cam or somethin else.... i have a vacum canister and no vacum leaks

 

Doubtfull on the cam but no idea on overlap and compression so it's hard to say but the vacuum canister should fix that.

Might be the pad material?

bret

 

i already have a vacum cansiter installed on the car the compression is 10.5 to 1 an 110lsa

 

Might be the pad material
the breaks worked fine with the smalll block that was in the car

 

That's not a very aggressive cam for a BBC so I can't see a vacuum problem. Check for things like the one way check valve in the vacuum line to the booster bleeding off.

Worst case is you'll need to install an electric vacuum pump for brake assist like GM did to some early 80's cars that had 4 cylinder engines.

Install a manifold vacuum gauge on the engine and go for a drive to see what kind of vacuum it produces during different situations. At an idle, most "street" cams will produce from 10 - 18 inches of vacuum which is more than enough to operate a brake booster. WOT should produce no vacuum but you're not going to be on the brakes at WOT. Part throttle varies.

 

You could just have a leaking brake booster.

 

how do i tell if its a leaking brake booster

 

Shut the car off for about a minute then pop the fitting out of the booster. You should hear air being sucked in.

 

yea it did suck air in... brake boster is fine going to get a vacum gauge now

 

Is it a power brake system or manual brakes?
If its Power its definetly due to the cam...Had the prob with my GTO i just Switched to manual no big deal,very common problem..

 

I would put a vaccum gauge on and find out if you have enough vaccum then go from there.

 

well i just put a vacumm gauge on it now and i got 3 inches of vacuum at idel at 850rpms. when i rev it up on the way back down it makes 20inch pounds plus.... i think i have a vacumm leak somewhere.... any idea how to find it

 

Yep. I have a slightly larger cam in my 496 and decided to go manual brakes for the time being because there wasn't enough vacuum to operate them correctly. Even the cam mentioned isn't small by any means.

 

my friend has a cam jst about 700 lift wuth alot more duritation and his brakes are fine

 

And its a power brake car?And he doesnt have any vacuum assist canisters?or a seperate vacuum pump?Id like to see that.