Disadvantages of putting 9" 3rd member in an 8" housing?

[danny clemens]

Haha I just found this old post Lew. I didn't do the mod to my rear end. It was yours I was talking about. Freddy(Clyde) tore up the Bronco rear end I got at Nigel's, I ended up putting it in the Cuda. Funny thing, the 65 fastback I picked up has a 9" rear with small bearing axles and tapered tubes in it. I wonder if it was a modded 8" to 9" or if that was how the 9"s came back then?

It was either modified or is a hi-po rear.

 

[bnickel]

It was either modified or is a hi-po rear.

sorry i should have said that in my previous post. but yeah the only way you could get a 9" in the 65-66 cars was the hi-po rear, and like i stated above that is how they came then

 

[ford_george]

9" rear

Are there any disadvantages to putting a 9" third member in an 8" housing? A local shop says that its possible, and I think it is too. I know the housing won't be quite as strong, but from what i've heard, its rarely the housing that breaks, so maybe this isn't a problem (not that I'm really putting that much power out anyway, but in eventuality, as I keep saying... I hope to). Will the third member be compromised at all? Will the housing be an achilles heel for my car?

If you want a 9" rear end for a 64-66 Mustang or for a 63-65 Fairlane, find a 1957-59 Ford, as they are the same width and the spring perches may also be the same placement for the Mustangs. I think the spring perches will have to be moved for the Fairlanes.

All 289 HiPo Mustangs and Fairlanes came with the 9" rear end and I think the Shelbys came with 31 spline axles. Mine did.