i have a 2004 mustang gt with a built engine installed. its got a MMR 4.75 shortblock with 9.0:1 compression, MHS stage 2 ported heads, CMS stage 3 blower cams, vortech v1 s-trim and all the supporting mods. my question is, what should my vacuum be at idle? i was looking at my gauge today at at 900rpms (idle) my gauge is reading around 10-11 vacuum. does that sound about right? thank you for yalls input.

 

should be 15-20 roughly depending on altitude and whatnot. But since you have a non stock motor, and a more aggressive cam i'd say your right around normal. Cams always take away some vacuum.