Haha. That’s why i asked about the manifold!
Yes i had issue (may still have) with the Edelbrock LT4 manifold.
I remachined both faces as it was sucking air from underneath the ports.
I even bought the tool to measure the head face angles and the manifold angles. The manifold was off quite a bit.
I think i milled something like 0 to 0.007 top to bottom off both faces.
Also check front and rear china walls that it’s not sat up on them.

I am a bit dissapointed in the quality of the manifold
I also drilled out one of the front idle ports as it’s smaller than the others.
I could be wrong but I feel these ports could need to be bigger.

Oh and again BLM’s are maxed on both sides.



Mitch