Topic: 68 rear end axle identification

[68Metuchen390GT]

I need some help from the experts. I have a June 68 Metuchen built 68 390 GT Fastback w a toploader. The original rear end was a 3.25 traction lok rear end according to Marti. The car is a former street racer. The 9 inch rear end appears to be have been replaced with I think a 64 Thunderbird rear end. I have attached a picture. It has a 64 date coded third member.

My questions are, is the axle housing the same on all 68s or is it different between the big blocks and the small blocks? How do you identify the correct axle housing if not? What does the correct ribbing on the third member look like? Thanks in advance.

[Bob Gaines]

I need some help from the experts. I have a June 68 Metuchen built 68 390 GT Fastback w a toploader. The original rear end was a 3.25 traction lok rear end according to Marti. The car is a former street racer. The 9 inch rear end appears to be have been replaced with I think a 64 Thunderbird rear end. I have attached a picture. It has a 64 date coded third member.

My questions are, is the axle housing the same on all 68s or is it different between the big blocks and the small blocks? How do you identify the correct axle housing if not? What does the correct ribbing on the third member look like? Thanks in advance.

There are 8 inch housings and there are 9 inch housing . Your car would use the same 9 inch housing like used in later 67-70 Mustangs with 9 inch center sections.

[68Metuchen390GT]

Thanks Bob, so the only difference would be the third member. I don’t see in the literature any part numbers or date codes on the housing is that correct?

[Bob Gaines]

Thanks Bob, so the only difference would be the third member. I don’t see in the literature any part numbers or date codes on the housing is that correct?

No a 9 inch third member fits in a nine inch housing . A 8 inch fits in a 8 inch housing . The 8 inch housings are at least 15-20  times more prevalent. Try West Coast Cougar.   

[68Metuchen390GT]

Sorry I meant the only difference in the 9 inch housings would be the third member sorry it made sense in my head.

[68Metuchen390GT]

No date codes on the housing?

[Bob Gaines]

No date codes on the housing?

Yes they are date coded however because of the location you typically can't red them when installed. Most are metal stamped so faint that you can't read even if you know where to look. Others are ether too faintly stamped or not stamped at all making them invisible. Nice un pitted housings are hard to find. With that said If you are able to find a nice one and you are able to see a date code don't pass it up would be my suggestion . You can make a date code disappear with little trouble . By the same token if everything else is date coded correct on your car like fuel pump,fuel tank sender,Battery etc. then a date code can be added if you want to go to the effort. To me some people get caught up on these nuance details while disregarding more highly visible ones. FYI be prepared to alienate anyone you are trying to buy a housing from after asking for a date code.

[Bob Gaines]

FYI the housings had a paper tag wrapped around the housing tube which identified it. There were no other engineering numbers. FYI the paper tag was not meant to last past completed assembly of the car so it is extremely rare to even find remnants of it let alone a legible tag.

[68Metuchen390GT]

Great info Bob. I’ve been lucky enough to find a correct date coded gas tank for my car so maybe I’ll get lucky with the axle.

[Scode67FB]

What"s that thing on the right side of the center section on the rear of the housing? It looks like it's where the fill plug would be on a 1967 housing. The Thunderbird housing is wider than the Mustang and would have "big bearing" ends as well as 11-inch brakes. Better pics of the third member would help, but I'm inclined to think it's more likely a "74" third member. Does it have a fill plug on the left side of the third member? If it does, it's definitely NOT a 64 third member.

[RoyceP]

It looks like you have a 1967 axle housing. The axle housing used in 1967 Mustang / Cougar applications is quite specific since it uses the "small" axle bearings it is tapered at each end. The spring U - bolts are the same ones used on 1967 8" Mustangs. The 1967 9 inch housing has a fill plug on the back, which yours has. Your car would use 2" brake drums, same as 8" equipped Mustang, even the same backing plates.

As mentioned previously the center casting should not have a fill plug for 1967.

The stuff you have appears to be wrong for 1968.

[68Metuchen390GT]

Thank you for the info, the rear plug is rubber. The plug has a Canada Patent and daisy made in America. The backing plate on the brakes is around 11 inches...best I can measure under the car. The date code is 4B25. Here is some additional photos, obviously not 68,but any help identifying is most helpful so I can find it a home.

[Bob Gaines]

It looks like you have a 1967 axle housing. The axle housing used in 1967 Mustang / Cougar applications is quite specific since it uses the "small" axle bearings it is tapered at each end. The spring U - bolts are the same ones used on 1967 8" Mustangs. The 1967 9 inch housing has a fill plug on the back, which yours has. Your car would use 2" brake drums, same as 8" equipped Mustang, even the same backing plates.

As mentioned previously the center casting should not have a fill plug for 1967.

The stuff you have appears to be wrong for 1968.

Royce , Not all 67 9 inch housings had the plug in the back .Starting sometime in May 1967 the transition began to occur to the style without the plug .That is why I described later 67 -70 being similar.

[RoyceP]

Bob regardless of all that his housing is 1967. The third member has a 1974 date code -  notice the two dots under the “4”.

[Bob Gaines]

Bob regardless of all that his housing is 1967. The third member has a 1974 date code -  notice the two dots under the “4”.

Royce, you made a blanket statement which by omission inferred that there was only one style of 67 housing and not a early and later style. I was clarifying that factoid for you in case you were unaware is all.