What does this tell me?

[Restomod Z28]

I'm hoping to get some feedback on this video - please really focus on the vacuum reading at idle. Can you see how fast it oscillates? I just swapped cams, and I went from a fairly steady reading at idle to this rapid fluctuation with the SAME gauge. Engine was torn down, cleaned, and reassembled when the cam was swapped. There are 1k miles on the short block.

http://www.youtube.com/watch?v=jAPHc...layer_embedded

In the video, I idle, I blip the throttle and hold it, I let it idle, I tap the pedal when the A/F ratio dropped, and then idle again.

I just find it hard to believe that going from a hyd flat tappet to a hyd roller with 3° more overlap would have this different of a vaccum signal. Is this normal, or is this indicative of a deeper issue? Compression or vacuum leak?

Thanks for any feedback-


Engine Details:
SBC, 383, 10.1:1 CR, aluminum heads, RPM intake, MSD ignition, Holley 650HP
New cam: 231/239° @ 0.05", 282/290 Adv, 112° LSA (Hyd. roller)
Old Cam: 230/236° @ 0.05", 274/286 Adv, 110° LSA (Hyd. Flat Tappet)

[anthonys 69]

Raped needle movement At idle this is caused by a small amount of combustion getting past an intake valves Your cam shows good valve separation so id take the valve covers off and re-adjust the valves. You can adjust the valves with the engine running You can back off each intake valve very slowly one at a time and watch the vacuum gauge, a little messy though

[TT302Z28]

Over tight intake valve......burned / bent intake valve......broken valve spring