1977-1980 Lincoln Versailles 9-inch housing width: 52¼"
Difference = 2 inches narrower.
Ideal backspacing on 17x8 = 4.75
Backspacing needed on 17x8 with rear 1 inch narrow = 1 inch less backspacing or 5.75 backspacing....commonly called "deeper dish" in the old school vernacular. However, since 275 40 17 actually works better on a wider rim, it would help to know what rim width you plan on running....but the math works out the same...what ever the backspacing requirements were for the stock rear, subtract 1 inch....so like a 9 inch rim 5.25 would in theory be the ideal backspacing and then you would subtract 1 and get 4.25 backspacing
I have a 68 with a lincoln 9" rear. My wheel size is 18 x 8 with 4.5" bs. You will need to go to a 9" wheel for 275's. I noticed when I put the lincoln axle in the tires sit back a little further than I would like them. I have put much thought in selling my wheels to go with 18 x 9's. If I did I would order them with 4.75 - 5.0 bs.
Well, I got the wheeels and tires mounted and on the car. I went with 5.5" Bs on the rear and 4 7/8 on the front. The rears are 275 40 17 and the fronts are 245 45 17.
The tires fit perfect with the versailles rear with no rubbing. The fronts fit perfect also. I did not have to roll the rear fenders, but I did with the fronts. The wheels are 17x8 front and 17x9.5 rear. Just passing on the info. Thanks for everyones help.
Well, I got the wheeels and tires mounted and on the car. I went with 5.5" Bs on the rear and 4 7/8 on the front. The rears are 275 40 17 and the fronts are 245 45 17.
The tires fit perfect with the versailles rear with no rubbing. The fronts fit perfect also. I did not have to roll the rear fenders, but I did with the fronts. The wheels are 17x8 front and 17x9.5 rear. Just passing on the info. Thanks for everyones help.