Dakota Rear Revisted

I found a 1988 Dakota rear that has the 10 bolt cover. It is out of the truck. The spring perches are the same as my 67 Fastback Cuda's (give or take a 1/8th or so). It is 62" outside hub to outside hub. This is what I need to get my 17 x 8 Bullits with 245 45 rubber under the rear almost perfect. My wheels are of the '05 variety and have a 6.29 back space why I need the wide rear). My question is this: Some one on the forum mentioned that some Dakotas had the 10 bolt rear but the rear was a 7 1/4 instead of 8 1/4. The visual clue was that the axle tubes narrowed down before entering the chunk area. The one i have found does just that! Don't want no more 7 1/4 junk. Any more advice before I put down a $100.00? I'm just crusin' with the 273, 4 barrel and 904. Not a G-Force Cuda! Thanks in advance guys