Hi Lupe,
When GM came out with the TBI, and TPI the modified the two center bolts for the intake so that they come through the intake into the head at a slightly different angle. The bolts screw into the heads at a more vertical angle than do the others. A couple of things you can do here. Easiest thing to do is buy another intake that is virtually the same but has larger holes for the 4 center bolts and come with an angle-type of washer that looks somewhat like a wedge to compensate for the different angle of the bolt. That way may be easier, but harder on the budget.
Way back when, I have been known to re-drill the holes in the heads and put thread inserts that match the old angles. That was for a different type of intake. If you are using an aluminum intake and are handy with a drill or air tool, you can take a drill bit or other cylindrical type cutting tool and open up the holes in an aluminum intake so that they will match the holes in the cylinder head. When I say open up the holes, I mean to take the drill bit and as you are going through the holes in the intake, hold the drill at a more vertical angle so as to align the holes with the holes in the head. Don't go crazy and make an oversize hole. You can then use some type of flat-washer on the bolt to cover the hole.
One problem you will have here is that because of the different angle, it is not going to sit flat on the intake surface. You can also sell your intake and purchase one that has the wedge-type washers with it. I am not sure if you can purchase the wedge-type adapters separately or not. Myself, since I am a Journeyman Machinist, I would find a way to modify it.
Another thing you might be able to do, if the intake is still in the box, you might be able to talk your supplier into doing a trade for one that will fit the Vortec heads.