71 dart resto mod, here we go

Ran into a snag, both 8.8 rears are different . Different splines so gonna cut down the mountaineer 3-7 posi disc brake and put under my 67 gt. Have to use the narrowed 8 3/4 that was also bought for the 69 in the 71 now as I have to be ready to run by aug 9th. Got the rms 4 link installed this weekend . Rear rocker is 2 1/2 inches lower than my 67 on ss springs. 10 inch mopar wheels will not work now with this rear now but the 275 60 15 will clear the frame rails on the stock cop car rims for now . Got to keep moving forward! Nwdart