I always check things and I am new to these Vortec heads. I have some 906 heads. But i am not new to porting or getting things to line up. These aftermarket intakes pose an issue. At least the one I got. It is a Jegs dual plane. This will be a long read but bear with me I have pictures to explain things and show you how to get it right. I have a feeling the misalignment may not only be this intake but others and this could be the issue many have with failed intake gaskets. First issue are the holes that bolt the intake to the head they are .473" diameter. The bolt is .310" diameter. I can move the intake back and forth on the heads .160". That throws off the intake port alignment. Those are pictures of where the gasket will ride with the intake all the way back against the intake bolts and all the way forward against the intake bolts. You ask HHHMMM Does the distributor care where the intake is at. Not on this intake ..as the hole is larger than the factory GM iron intake hole and the distributors are much smaller where they go into the hole. You get that overhang on the beaded gaskets and you will for sure get a leak eventually. Now if I split the difference the intake lines up to the ports just fine. How do I know what the difference line is when plopping the intake down onto the heads. Good question as the intake gaskets can move on the head also and how would you know. I trim the gasket so it is flush with the front of the head and this is my reference point so i know the gaskets are lined up with the ports on the head. A picture for you. Notice the arrow pointing at the trimmed area.. that spot is flush. Now if your gasket did not hang over or is short of the end .. you could scribe a line on the head. Now placing the gasket onto the head and the intake onto that and keeping it all lined up. I took a sharpened pencil and drew a mark on the gasket as to where it all rests at when snugged up. Now I unbolt and flip my intake onto the bench and line up the gasket to the drawn line from the pencil. Perfect alignment. Yep you notice the area I could port larger. But that is another story and I will not port here just yet. Hope this sheds light on some failed intake gasket issues. Or could be this intake is just drilled too large in the mounting bolt area..I have not measured any other Vortec carbed intakes. But the larger holes are actually a good thought as you have no idea how much milling a guys block and heads have had. I have taken .060 off the heads and .025" off a block and ran the .015 head gasket and a stock intake was never going to bolt on until I elongated the holes or drill them larger. Still up to the installer to line it all up.