Quick Backspacing Question

71DodgeDemon340 said
Im running sbp axles with a 1 inch billet aluminum adapter to go to bbp wheels, the 1inch adapter gives me more room to my leafs, im running a 275/60r15 on the rear and have about 3/4" of clearance between my sidewall and leaf and about 3/16" to my quarter lip. If i didnt run them id be limited in rear tire width, still thinking i could squeeze some 295/50r15's on there but wheels arent wide enough lol

The 1" adaptor doesn't give you any more room, it just changes the amount of backspace needed. And since you didn't mention the backspace you have, the presence of an adaptor doesn't mean anything to us. If your wheels fit, you obviously have about 1" more backspacing than you would need if you didn't have the adaptors.

Also, Dart's do not have the same size wheel wells as Dusters/Demons/Dart Sports. Without moving the springs you can't get anything bigger than a 255 on a Dart, and most people find that even a 245 is cutting it close for clearance even when everything is centered perfectly.

On a Duster/Demon/Dart Sport 275's are easy with the stock spring locations. A 295 requires a 1/2" offset and a quarter lip trim if your wheels are actually inside the wheel wells. If you're running SS springs or have the back end of the car jacked up then it doesn't matter as much since the quarters will be well above the tires anyway. But that's not the same as fitting.