Hey guys hope u can help me out here..

I have a Motne SS Thunder Car race car with a
edelbrock 2101 intake , a Isky LS1 cam 410 Lift and 290 Dur cam and a 500CFM 2 barrel Holly carb my problem is im only getting 12 lbs vac and i need 17+ lbs to run the power assisst brakes. Is there any way to get more vac to run the brakes. Right now im pulling the vac off the intake and i dont have the brakes to stop the car the way i want to i have to let off the gas way before the corner and that is were im getting bet.

Any help would be great Thanks  

I must say that's an incredibly poor choice for a cam and that is the root of your problem here...

A vacuum canister can help improve the vacuum signal by giving a sort of plenum for the vacuum to build into but it won't work miracles. The only way to pick up five inches of vacuum is drastically reduce the amount of valve overlap.