looking at the 440source website it shows some compression ratios in the low nines which is what i have. anymore i look at overlap at .050" for these scenarios. a stock cam is -11 degrees at .050". from the cams i've used I've found anything at zero degrees and above will noticeably effect low rpm vacuum. the summit 6401 has about +1 degree overlap at .050" but can reduce idle vacuum by 2". the mopar 272 has zero degrees at .050" and will reduce vacuum. my favorite performer was the engle 2330 but at 110lsa it will noticeably reduce vacuum at idle. adding a higher ratio rocker to a stock cam will add some area under the curve plus some lift but will reduce vacuum a little. enhancing the timing curve only marginally helped vacuum. there're no free lunches here or magical cams. it all needs to be thought out. of course, a vacuum reservoir canister can be added; i just couldn't find a decent place for the black lump in my engine bay.