Need to confirm axles

[Southpa]

I finally got around to measuring my rear end "width". I was reading in earlier threads that there were 2 sizes in 1970 half tons, measured between their respective "wheel mount surfaces". The early 1970 at ~62" and later 1970 at ~63.5" Mine is the latter at around 63 3/4.

OK, with that established can I take donor 5 lug axles from any 1971 - ? Chev or GM half ton truck?

[Southpa]

ttt , anybody?

[Hottrucks]

wiould like to know too..now I'm going to measure my axle If I don't have the short one I could use the extra 3/4" on each side to get my rubber off the inner fender lip

[swierker]

I'll take a stab at this although I'd like to hear some answers from others as well.

The length of a 71- up axle is 31 5/16" x 2 =~ 62 1/2 +~ 1" (the space between axles) = 63 1/2. Id say that you are good to do the swap.

The older axles are 30 1/2" I think. Which would make sense using the same equation to come up with 62" as you said.

I have a donor rear I think I might just use the axles from and put them in my 70 rear already on the truck. I think it's the wider one, but I've only measured from backing plate to backing plate and they are both the same. I will know soon, I just got the last of my parts today to do my drop/disc/5 lug conversion.

Dan

[swierker]

One other thing that I noticed. Every vendor I have seen lists the 70 axles along with the 71-up. I have read on here a couple of places that the width switched over sometime midyear on the 70.

So why do ECE, CPP, Moser engineering all list the 70 axle as the wider version? Can anyone confirm the mid year switch or are the vendors just "rounding" off the years?

[Hottrucks]

ANd

my truck is 6 lug?? 1970.. did they make them both ways??

[swierker]

Originally Posted by Hottrucks

ANd

my truck is 6 lug?? 1970.. did they make them both ways??

Not that I am aware of. I was just pointing out that the 5x5 wider replacement axles listed included 70.

It looks like the 70-up 6x5.5 is listed for 4wd.

[Southpa]

Some interesting reading here:

http://en.academic.ru/dic.nsf/enwiki/433284

I got a couple weeks off beginning next week and I'm keen on getting some things done. So far its been up and down, good and bad. I was given a set of solid aluminum slotted mags (good) which prompted the need to switch the rear axles. Its either that or try to find an entire 71 or 72 rear end for my coil spring truck.

I figured they anticipated using wider rears so manufacture began in mid 1970. The above link mentions that they switched to 5 - lug because it was "common to Buick, Oldsmobile, Pontiac, and Cadillac passenger cars." I guess that means that the lug patterns on the cars and 1/2 ton trucks of the time were the same? Makes sense at the factory, anyway.

I'm still waiting for a bumper and brackets, ordered them on July 2nd locally. The guy who placed the order is no longer working with the outfit and they don't know what is going on. I'm glad I phoned them and got things kickstarted or they would still be in limbo. I wouldn't care so much, ya see, but they already got my money! They say early this week...lets see if I can stay civil.

[68chevyfuelie]

As far as I know, the newer 73-81 12 bolts will fit in the stock 67-72 location, the only difference being wider and different shock tabs (and obviously coils vs. leafs). And yes, on the newer/wider 12 bolts, the only difference was axle shafts. I've got a 73-81 12 bolt in my '68, someone fabbed custom shock tabs, if I want to go 6 lug I just change axle shafts. I may be corrected, but you can mix and match the newer stuff all day long.