just some pics, I put most of my stuff on IG and don't contribute to TGO as i should.
'85 firebird 305 quadrajet 700r4. its a turd. the rear diff was whining terribly when I bought the car a few months back. Probably the worst I've ever heard.
I was planning on doing a simple refresh but discovered it was a 9bolt and not a 10bolt as expected. Common experience seems to say the 9bolt is stronger. I didn't care that much and I wanted ease of rebuild and parts so I pulled a 10-bolt drum rear out of a '92 305 camaro to rebuild. I have a full LT1 brake setup to swap later, I didn't feel like dealing with those neaunces right now.

-10 bolt drum car.
-3.42 gears from 3.08. bought used on ebay, setup (paint) pattern will be a bit different
-Detroit Tru Trac Hellical diff
-Ratech rebuild kit with all new Koyo (made in USA bearings), seals, etc and their smart-sleeve (crush sleeve)
-stock axles. good enough for my power level and future LT1 brake swap.
-welded on drain plug
-fab'ed control arm and track bar relocation brackets; I plan on dropping the car 2" front 2.5" rear in the future
-new shoes, cylinders, hose
-cleaned & painted everything

0.075 backlash
22 inch-pound pinion bearing pre-load. some will say thats alot but '85 & '95 firebird manuals spec 15-30 inch-pounds preload and another 2-5 for a completed assembly.

starts off with junkyard crawl pulling the diff out of the donor. what a PITA.

 

continued. shop dog included.
https://share.icloud.com/photos/0JI_...MT0tnLDXaSsoYA
https://share.icloud.com/photos/05sc...RfebY75-N3QbJg

relocation drop seems a tad much but i plan on dropping the car 2.5" in the rear. I measured to get flat LCA's. also have a few extra hol3s if I want to change my instant center.

 

calibration to determine 700R4 speedo gear changes to correct the reading as well as a shot of 'Turd Bird' after I picked it up few months ago.

 

40/15 gear combo was about perfect to dial in the speedo. I think the parts were $45 on amazon including the aluminum speedo housing.

and only because it looked so terrible in the original pic i'm posting an update. It is now shiney:

 

Good work.