a903 to a230 swap in 64 dart gt 225 slant 6

I believe that the 230 takes the same pattern as an 833, I have attached a photo of slant 6 bellhousings a 64 slant 6 833 bellhousing should be what you are using for the correct placement of the bell crank. As for a bolt in driveshaft a 66 Dart driveshaft should fit as long as it is for the same rear axle.