ford 9" - 8 3/4 rear???

[delrio wagon]

I am having a problem with rear end selection. As I understand, I guess my rear end is a 8 3/4. I took it out of a 57 4dr wagon years ago and saved it. I never needed it until I found my Del Rio 2 dr wagon (rear was already gone). My problem is I am going with about 300 horse 390 and this rear is a 4.11. I want a comparable ratio so I can at least drive it a 100 miles without breaking everything. I have a 68 Galaxie with the ratio I want and a posi to kick. Can I take out the 3rd member and put it in my 57 rear assembly? I am also not sure of axle spline, which to use, if I have to have the one in the Galaxie shortened etc? Poor Boy just wants to drive my 57 wagon. Thanks for any help.

[wolfpupsdad]

 ok heres the story, all ford third memebers from 1957 til whenever are all considered 9" tho 57and 58 do have a small ring gear. you can put any 9" ring gear in a 57-58 third memeber but alil trimming may be required. my 57 third member needed alil grinding for a 3:55 to be installed but no big deal. now on to axels. your 57 will be 28 spline and i bet your 68 are to. i'd say , slap your 68 third memeber in your 57 housing and go.

[shopratwoody]

I second that. Mines had everything from 3:0's to 4:88's and they all fit fine. If that 68 isn't a
H.P. model it'll be 28 spline also.

[delrio wagon]

Thanks for all the info. I have heard strange stories about the rears being so different. I figured the best way to know for sure is to ask here, where the info is reliable.