Valiant 7 1/4 differential

I have pulled apart the original 7 1/4 rear end to change gears from 2.94 to 3.23. I had purchased the 3.23 gears on ebay new for $50. almost two years ago and all looked OK at first, however the pinion end is 7/8 fine thread on the 3.23's as compared to 3/4 fine on the originals. The ring gear bolt holes are 5/16 LH thread compared to 3/8 LH for the originals. I checked against a parts car 7 1/4 from a 69 Barracuda and they are the same as the original Valiant parts. Has anyone else run into this. Are the 3.23 gears possibly from a very different application? I haven't found 5/16 LH ring gears bolts and am not to sure about using them in a differential drilled for 3/8 even if I did find them. Any help would be appreciated. Might have to look for more compatible 3.23 or 3.55's.