looking at Crane recondations, you going to have a lot of low end problems. Those cams require a 12.0 Compression ratio which means the overlap is enough that the static ratio is dropped a great deal. Static ratio is the compression ratio you are left with after the overlap is factored in.

Without knowing the exact duration at .001 I cant tell you what kind of IDLE ratio your going to have if you still want to attempt running the 10.5:1 shortblock

If brakes are your concern right now then start hunting for a Vacuum pump setup or convert to manual brakes.


Edit: found one listing that claims they have a duration of ADVERTISED 258 degrees. That is very close to the Crower 3 cams and you will prolly get away without any type of canister or check valve if you tune it right. Your Crane 16's are an Advertised duration of 250 degrees. The 8 degrees wont be noticable Tune the idle to the vacuum like your supposed to and it will be fine. For what they consider a "drag" cam, that duration isnt that big. Street cams are usually no more than 280 degrees of duration. Even the 4g63 street cams run a duration of 272 degrees. Factory 420A cams are 222 degrees; thats only 30 degrees more.

I dont see how they can claim a 12.0: ratio is required. As long as you have 9.5:1 your fine

Your poor vacuum now is becuase your not tuned to the cams. The maps are tuned to the factory profile. Once you tune the idle fuel and idle timing you should be at least 10" of0 vacuum at 800RPM. If you raise your idle to 1000 then you should be able to get 12-15" out of them.