On the street;
275/60s want a wider rim, that's why normal pressure is lifting the edges and puckering the first inboard treadband.
I use the 85% rule;
a 275 is 10.8 section (275/25.4=10.8); and wants a .85x10.8=9.2" rim; rounds to 9", if you can find one. I used an 8.5 which then works out to 8.5/10.8=78.8% too narrow but what can you do. A 10" rim would be 10/10.8= 92.6% which is too wide, probably pretty hard to install.
With the proper rim width, you will be able to raise the pressure back into a safe street pressure, altho I have gotten used to 24 in my 295s on 10s...
And if you run a tire on a too-narrow rim, with too low a pressure, I have found that it likes to eat the two treadbands first inboard from the edges; not the outermost. And if you get the tire up to higher MPH,It will try to grow and burn off the center 3
And if you run it at too high a pressure, it will burn off the center three.
When you get down to 24psi, the tire, on a narrow rim, in a corner, will roll over onto the sidewall, which, the first time you feel it, is freaky! I have gotten used to it,lol
But 275 BFGs are too skinny for a 440 anyway. 295s can be fit into a 68 Barracuda tub no problem; and I was thinking the Duster has the same tubs, but I don't know that for sure.
IMO, the widest tire for an 8" rim is 8/85%= 9.4section, which is 9.4x 25.4=239 in metric speak; so a 235. Guys put 245s on those and lower the pressure some to get away with it.
Hope this helps
