[HeadDoctor]

How many blocks have you ever seen that were square from the factory - even some of the after market blocks need to be "Square-Decked"

As far as creating a misalignment that depends on how much is cut off the deck surface, it usually only takes .010 to .020 to straighten it out. Also how much is cut off the heads so its the total of both that affects the manifold.

Zero decking means that you have to assemble one of the pistons in the block and check the (TDC) deck at all 4 corners. The problem lies in - if the piston is down in the hole .040 and you want to run zero deck then you have to mill the deck that far or change something in the rod-piston dimensional configuration.

The .040 on either the deck or the head is going to cause a slight misalignment of the manifold.

Denny@JDS INduction Products.