Honestly, lots of car's seats require the use of a pool noodle to get a rearfacing carseat at a comfy and safe angle. It's not unusual at all. So many cars have those seats that slant.
It seems to me that most convertible carseats recline exactly the same, since they are made to recline to 45 degrees for a newborn and it looks like they test that on a level surface (which your car's seat is not). So, many will need a noodle.
The Radian leans back really far and may not need one (don't know if it's even allowed--someone here will know). That's one complaint about it for some kiddos--they don't like being so reclined when they are older.
The Complete Air often needs noodles to get a good install, but I think the Deluxe version has a base that makes that unnecessary (or at least easier).
The Radian, Complete Air, and True Fit will all last much longer than the Blvd rearfacing. The Evenflo Triumph Advance will last a smidge longer. It may recline a bit more, but we used noodles w/it in our Passat that has slanted seats (and I'll bet they're not as slanted as your new van).
I found the product that is made to use in place of a rolled towel or noodles much easier--esp the one that is shaped differently on each of it's three sides. That way, one product worked perfectly no matter what vehicle we moved the seat to.
hths
henrietta