what kind of problems will i run in to , putting a 83 gsl rear end in to my 79

 

none really, you are going to have to change your master cylinder and your e-brake cable, otherwise its just a bolt in swap.

 

not quite that easy. 79/80's have different threads on the brake lines, you'll have to do something about that. Not a huge problem, but very important to do.

 

are the driveshaft flanges the same?

 

I think 83s have the larger driveshaft flange

 

why can't i use the stock master cyl?

 

Becouse you need one made for 4 wheel discs

did you already have 4wheel discs?

 

Oh ****, good point, 83 and up have the different driveshaft. The master cylinders are different. the drum one puts a more balance to the rear than the disk one would, leave the drum master in and slam on the brakes and you'll go pulling 180's everywhere.

 

wont the driveshaft flanges switch out on the diffs with out taking too much apart?

 

its easier to just switch the drive shaft

 

you can get ss brake lines from mazdatrix with the threads you need