Hotch,

"Am I gonna blow out?"

Perhaps.

I believe that the ratings on the tire are the correct ones.  Specifically, 
you need to be sure that the tire can support your vehicle, and at what 
tire pressure.

In my case, the original light truck tires (4 ply, 6 ply rated), and
the reinforced passenger tires were rated at about the same maximum load. 
 However, the light truck tires were rated for that load at 50 psi, and the 
reinforced passenger tires at 40 psi.  (I don't remember the details about 
the intermediate Bridgestone tires since I only had them a week or so.)

The door jamb on your Vanagon should list the weights for front and rear 
axles.  Use that to determine if a specific tire has a high enough load 
capacity.  I think that my Vanagon only lists the light truck tire 
pressures on the door jamb.  However, the owners manual has both of the 
tire types and pressures listed.  Perhaps you don't have an owner's manual 
for your Vanagon?

There is lots of controversy over what is the "best" tire.  Beyond my 
experience that I have already related, I would emphasize that any tire you 
consider must have the load capability and should be inflated to the 
pressure necessary for that capacity as recommended by the tire 
manufacturer.

Mike