Rear end info

7173Mustangs.com

Help Support 7173Mustangs.com:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
Feb 16, 2011
Messages
3,495
Reaction score
11
Location
Monument, Colorado
My Car
1972 Sport Roof
Alright, so talking with my Pops today he said that the rear end came out of the donor T-bird (that gave up the engine and trans). I thought he had pulled the rear end out of an Explorer. I was wrong.

Turns out, it's a type that I know nothing about: a 9.3"! Does anyone know anything about the 9.3" diffs? I know they do share some similarities with the 9" rear end, but that some parts you can't swap.

Edit: ratio is 2.80:1, non-limited slip.

Obligatory pic:

2w2ois6.jpg


 
Last edited by a moderator:
The bolt pattern on the rear drums is 5x4.5". I saw the fordification page, but I was hoping to get some first-hand info because I've never even heard of a 9.3" rear end until today. I've found some stuff on Olds/Pontiac 9.3" diffs but I don't know if these are the same as the Fords.

 
Interesting! Did your Pops do the swap? Was it a direct swap or did he have to do the typical modifications? Never heard of a 9.3" Ford rearend and why the extra .3" on a perfectly engineered 9"? Would like to see a complete pic of the rearend on your car.

 
Ford used them in larger, heavier vehicles. The ring gear is actually 9 and 3/8. It is not well supported by the after market. If you want a traction-lok and a different gear set it would be easier and cheaper to find a whole 9 inch center section. Chuck

 
Interesting! Did your Pops do the swap? Was it a direct swap or did he have to do the typical modifications? Never heard of a 9.3" Ford rearend and why the extra .3" on a perfectly engineered 9"? Would like to see a complete pic of the rearend on your car.
Yeah, his neighbor had a 1970 Thunderbird (18' long, and you thought OUR cars were big!) that he bought the entire driveline out of. He had it rebuilt and shortened the drive line, I think he had to have some mounts fabbed up. I found it pretty interesting too.

Pic before taking it out of the T-bird:

29uobag.jpg


Pic of it in the Mustang after the rebuild:

2hg9u1s.jpg




Ford used them in larger, heavier vehicles. The ring gear is actually 9 and 3/8. It is not well supported by the after market. If you want a traction-lok and a different gear set it would be easier and cheaper to find a whole 9 inch center section. Chuck
That's what I thought too. If I want to up the gears I'd probably swap it out. I may just keep it though, 2.80:1 is good for highway driving, right? This is going to be a cruising car, not a drag car.

 
Last edited by a moderator:
With the 429, no problem. The ratio should be more than fine for a cruiser. My high school car was a '73 Gran Torino Sport w/ a transplanted 351W/FMX/2.75 gear and had no "wishes". Well, not that many.

Matter of fact, when I used to drag race the car (1983), there was a bone stock '70 T-bird (hideaway headlights, suicide doors I think) that ran 13.99's all day long against my 16.40's. Guy only removed the air cleaner, back seat, spare tire, etc. and ran those numbers with burned out G'year Eagle NCT tires, no slicks. It was a hoot to watch.

Fear not, the long legged 9-3/8... :)

 
Back
Top