Using a chisel can be dangerous....especially when it is an aluminum intake. While you may have the cast on there now I wouldn't get in the habit it using a chisel. A putty knife (I use a taping knife personally) will easily slide between the intake and block for the valley seal and between the head and intake to start breaking that seal. I find once you break the block seal in the front and back and intake seal to cylinders 1 and 5 you can then usually grab a hold of it and get it the rest of the way off by hand.
For a laugh...here is a picture of my in the same place you are several years ago. All the hoses out, all the bolts out, everything out of the way, and I couldn't get the intake to budge. I literally picked the car up off the jack stands with the cherry picker by the intake with nothing more than the rtv holding it on.