Alignment issue with Edlebrock manifold on SBC w/ Vortec

[David67]

We have an Edlebrock Performer manifold for a SBC 350 cid with Vortec heads. The manifold bolts have the correct threads for the Vortec heads, BUT the holes in the manifold are a bigger size, so the manifold can shift front-to-back a little.

Should we just center on the bolt holes or is there some trick to ensuring the airflow paths are smooth at the interface? It seems a little misalignment of intake manifold ports with intact head ports would be a VERY bad thing...

Thanks.

Mark