-I-,
285/75/16 and 305/70/16 tires are in the 33 inch catagory. 315/75/16 tires are in the 35 inch catagory. So, you already have 33's.
Dan.
PS, Hey Bill, was that with the cruiser backed in or nosed in. I'm still visualizing your install with one leg hung over the edge of the bed ::)
If the springs are in backwards you would have a noticable lean to the left. As caster is the "return to center" I would imagine that will help when it's corrected. When you lifted it did you notice if your steering wheel was still "on center"? If it was not and you removed it and re-centered...
.02........
In my automobile owning life time (some 30 years now) I have modified several nice-driving cars in various ways for various reasons. More than once what I did LOOKED good but sucked when it came time to drive it someplace. I wish I had a bunch of that money back, it was an...
IIRC, some of the vibration will come from the front driveshaft. that is why Christo says you need one with a cv joint in it. You could pull the driveshaft and lock the transfer (you do have a CDL switch,no?) and go for a ride to see if it's still there.
Welcome.
Go to Christo's site: www.sleeoffroad.com and read his well laid out information regarding the modifications required to run 35's and that much lift. In quick summary you will need adjustable panhards front and rear, front leading arms, rear adjustable control arms, front driveshaft...