Wow, I never knew about the 9 bolt!? Weird!

 

I thought it might have been like a secret. I guess it is in a bad way.

 

Wow, so much misinformation about the 9 bolt in this thread.

It was actually used from 85-89. Some early 90s might have come with them. It was an upgrade used in higher hp 3rd gens, especially behind the L98s. The ring gear wasn't much bigger than the 10 bolt used during the same years, it's greater strength came from a stouter posi unit w/4 spiders, also has thicker non c-clipped axles.

Holden kept using the 9 bolt, and a version of it ended up under the modern GTO, upgraded to an 8" ring.

Not a huge strength improvement over the 10 bolt, and the difficulty of getting parts for it = not much reason to look for it as an upgrade. If you happen to have one, good for you. But if it needs repairs or a posi to replace your worn out one (cone type, non rebuildable), $$$.

Biggest reason GM quit using them was the cost of importing them from Australia. 10 bolts also improved over time. In the early 80s GM quit offering posi 10 bolts for a while cause they were breaking behind the cheezy 305s of the time. The castings would even warp from the TA mounting bolt's torque. Chevy nutswinger extraordinaire Doug Marion even had to criticize GM on the sad situation in Super Chevy. 1st and only time I can remember that happening.

I had an 89 Formula 350 twin cat with a 3.27 9 bolt under it. Should have never let go of that car.

 

It was used for more then one year. It wa standard on all 350 engines and manual 305 TPI's. It was strong rear and was deleted from production due to the import costs by GM. One reason for its dislike is the shortage of replacement parts. So don't blow smoke when you have no knowledge of the subject.

 

I was apparently mistaken about the years of production, but I still know for a fact that from a production point of view, the rear end was not a high quality piece. The rearend had horrible welds that were way inferior to the 10-bolt from GM and the machining wasn't nearly as tight as that of a GM. In more simple terms...the rear was hacked together. I'm sure it is a fine rear, but the extra ring gear diameter doesn't make it any better than the 7.6 we have.

 

I also KNOW as a Fact that BW 9-bolt rears were better in strength & quality then the weak 10-bolts. So you have your point of view and I have Mine. Besides I have a 9-bolt under my car. What do you have???

 

Alternately, the Dana 60 is now available for the 4th gen Fbody. Strong as all get out, but HEAVY.

 

Is it stronger/heavier than a 9" Ford?