Manifold spacers ?
 

We're installing the Edlebrock Performer upper and lower on our 331, the vacuam connector on lower side of upper didn't clear the valve covers, we need to use due to the 1.6 rockers.

We just picked up an Edlebrock spacer which gives us the clearance. Any comments on using these pros and cons? We noticed there's two bolts in the center of the manifold which are not used with the spacer.