5.2 Plenum Gasket blown, good info here
 

Ran this test today...
I have pure vacuum doing the second part of this test...
Plenum gasket failure...
Hughes kit to be ordered...

Hugh's kit coming. Will be here in 4 days UPS ground. I will hopefully post the repair process. Or at least the test before and after.

Don't over torque the manifold bolts. I think it's only about 11-13 ft lbs starting from the center out. Over torquing can actually crack the block around the cam journals.

Well it was blown. Put the Hugh's plate on the bottom and this thing is unstoppable right now. It actually drives like a v8.

Good job!