Posi ?

[schmedly]

My 67 came from the factory with posi. I would like to swith to five lug and disks in the front. I have a 71 I can rob the disks off of but what would I have to do to change the rear to five lug and ballpark what would it cost. I do have access to a pretty nice machine shop and an outstanding machinist. Is it as simple as pullying the axles filling the holes and drilling new or is there a better way that is cost effective? Thanks for all your help. You guys and gals are the best.

[stsalvage]

do you have Rear Coil springs or leaf springs in the back of the truck. If the 1971 is the same truck as in drive train

If your truck has ladder bars and the other one have leaf springs you have some work in front of you But if there the same in the back everything will bolt up and most of those 1971 1/2 trucks had posi in them one way to tell jack it up Put it in neutral and spine the tire if they both spin the same way your in luck.

where both trucks Auto's or stick shifts More people will chime in on this one My 1971 had posi but wish it had the ladder bars with the 12 bolt posi

[schmedly]

Both are coils with 4 speeds. Not positive but i am pretty sure the 71 does not have a posi in it. I know for sure the 71 does not have the original rear end in it.

[schmedly]

couple pics?

[texnician01]

In your case there are two ways to do this:

1.) Swap the entire rear from the 71 to the 67 and then simply move the Posi carrier from the 67 axle and install in the 71 axle housing. This way would allow you to rebuild the rear at the same time leaving you with a virtually new trouble-free rear.

2.) Swap axle shafts from the 71 into the 67. the only issue with this is you will have to make a 0.75in spacer to put behind the brake backing plate on each side as the 71 axle is 1.5in wider track width.

The posi carrier will fit into either rearend and the axle shafts will fit either rear with the only concern being the 71 axle shafts are 0.75in longer. Hope that all made sense, if you have questions feel free to send me a message. One other question, what is the axle ratio in each axle? You, of course, will need to keep the ring and pinion sets matched up. If you have one axle that has a 3.07 ratio and one that has a 3.73, those are a different series carrier and you cannot swap ring gears from one carrier to the other. The carrier can still be physically moved from one axle housing to the other but the ring and pinion set will have to move with the carrier. If they are both the same ratio then of course that isn't a concern, you just have to keep the ring and pinion together as a set. You will need to set up all of your backlash, preload... if you move the carrier from one housing to another. If you move the carrier and reset a used ring and pinion it may make some noise until it establishes a new wear pattern.

Good luck

Nathan

[tubbedII]

I've seen axles where they have welded up wholes and relugged them, but I don't know how safe it is...if you trust your machinist, ask him and see how much it costs.

You could also go the new axle route from CPP rather than using the spacers and 71 axles.

I would think using the existing rear so you don't have to pull the posi would be cheaper unless you can swap that on your own...

[schmedly]

My machinist is outstanding and since i helped him restore his wife's 66 chevelle he works real cheap too.