Rear end swap?
 

Ok i couldn't get a response on the other forum so ill try here.. i have from what i was told was an 83 LSD rear that im going to swap into my 82 S. My only issue is the 83 has the large flange with through holes for nuts and bolts while the 82 has the threaded flange. Can i drill for the smaller bolt pattern on the 83 flange? or can i swap the flange from the 82 onto the 83.. i dont want to mess anything up in the rear by swapping the flange. any info would be greatly appreciated

I believe you have the '84-85 rear due to the flange size that you are mentioning. IIRC, the 79-83s had the smaller flanges. The easiest way that I would suggest for you, and I would recommend this anyway for balancing purposes, is to change out your driveshaft that goes with the rear end. This was everything will bolt right up. Mark your driveshaft for alignment/correct balance points, if it's not too late. Hope that helps.

after reading around and searching the 7 club.. mazda apparently made teh change 1/2 way through 83.. so i might have an 83 1/2 rear.. and i seen a rear swap where someone took and swapped a gsl rear and then changed the mating flange on teh diff.. my only concern is if it will mess up pinion lash etc etc when i change the flange

I wouldnt swap the flange. I'd swap the driveshaft. I always match a driveshaft with the rear... just my two cents.

You are correct, the rear changed to the big bearing style late in 83...so a few 83s had the 84-85 style. FireGSLSE and I were discussing this the other day :)

Yeah, I'd just find a matching driveshaft. Shouldn't be too hard, I imagine, since they came on all '84-'85 cars.

Edit: is the large flange an accurate indicator of a big-bearing rear end?

im not sure i searched for a bit on looking for this bu noone on 7club remembers if it was or not due to the fact that it was a mid 83 changed. It could be, it might not.. i might replace the bearing on mine before i put it in so ill know for sure when i do.