'84 rear to '66 swap?

[66coffin]

do any of you know if a 84 1/2 ton rear end will bolt up to my '66 c20? i'm converting to 5 lug, well that's the goal anyway. thanks fellas.

[62gmc910]

After some cutting welding and fabbing

[Chevy Fleetside]

Dose your C20 have leaf or coil springs? Coil springs means welding perch mounts and something for the panard bar. If it is coil springs then I don't really know...

[66coffin]

thanks guys, i have coils in the back and was hoping for a straight forward swap, just bolt it up, so i'll pass on the '84 rear, thanks again for the input!

[ruffrida2005]

the only straight swap on our trucks is from 63-69, but none of those are 5 lug, You can just buy 5 lug axles and swap. 71-87 rears are wider then the ealier 12 bolts.

[Chevy Fleetside]

71 and 72 diffs are straight swaps.

[ruffrida2005]

I've heard diffrent about those 2 because they are wider.

[jgh64pkup]

the 71-72 work fine
i have a 72 in mine with the stock 8 in ralley with a 275 60r15 drag radial and it has plenty of clearance

[62gmc910]

The 71 72 s bolt right up but the track is a bit wider I believe 1 1/2 inches Captainfab would know for sure

[Captainfab]

That is correct. The '71-'87 rear differentials are 1 1/2" wider overall than the '63-'69 rear differentials. The 1970 differentials can be either width I believe, depending on when in the year they were mfg'd.

So yes the '71 & '72 rear's are a bolt in 5 lug swap for the '63-'69 trucks. However when installed into a '63 or '64 truck the different panhard bar will have to be delt with.

Originally Posted by 62gmc910

The 71 72 s bolt right up but the track is a bit wider I believe 1 1/2 inches Captainfab would know for sure

[66coffin]

Originally Posted by Captainfab

That is correct. The '71-'87 rear differentials are 1 1/2" wider overall than the '63-'69 rear differentials. The 1970 differentials can be either width I believe, depending on when in the year they were mfg'd.

So yes the '71 & '72 rear's are a bolt in 5 lug swap for the '63-'69 trucks. However when installed into a '63 or '64 truck the different panhard bar will have to be delt with.

Captain, you say the pan hard is different and needs to be dealt with if the 71-72 rear goes in to a 63 or 64, but what about a 66, is it the same deal? if so, whats the best way to fix the problem? what is the problem exactly?

[62gmc910]

If the truck has a "66" rear housing it is a direct bolt in . the panhard hole is cast into the housing at about the 2 O'clock position same as the 71-72 axle
if it has a 63-65 housing the panhard bracket is a fabricated piece on the RH axle tube.
Upon actually reading your OP the C20 axle will prolly be a fabbed assy so maybe the panhard bar from a 1/2 ton will be needed. if you look here http://67-72chevytrucks.com/vboard/s...d.php?t=382643 the pics show a later prolly 73-87 axle in a C20
Captainfab can prolly build you a set of axle a saddles with your choice of drop built in for the later 73-87 axle

[ruffrida2005]

Well that's good to know. I wasn't for sure if the did mount up because they are wider. I guess I didn't think about the frame being the same from 63-72 so the trailing arms would be the same.

I stand corrected.

[Chevy Fleetside]

Gee I hope the 72 bolts in seeing I have one in my 65. Here is a picture of a 72 diff in my 65.. and one with the bed on.. Almost forgot to mention, I also have complete front suspension from a 75 chevy truck bolted on my 65, 1/2 ton crossmember.

[66coffin]

here is a pic of the 66's rear end, is this the 63-65 rear or a 66 housing? will the 71-72 bolt up to this panhard or do i need the 1/2 ton one?

[62gmc910]

The 5200# rear has a fabbed panhard mounting bracket. making a 73-87 diff swap easier if you want to go that way. If you find a 71-2 diff in good shape you will need to get the panhard bar that is attached to the 71-2 diff. the fuel tank in Chevy Fleetsides pic hides the panhard mounting

[Chevy Fleetside]

Originally Posted by 62gmc910

The 5200# rear has a fabbed panhard mounting bracket. making a 73-87 diff swap easier if you want to go that way. If you find a 71-2 diff in good shape you will need to get the panhard bar that is attached to the 71-2 diff. the fuel tank in Chevy Fleetsides pic hides the panhard mounting

I used my stock 65 panard bar. The one in his picture looks like an early model.

[62gmc910]

'Cause its on a 5200# axle I have a '72 C20 with the same set up Coffins truck is a C20

[Chevy Fleetside]

I also have a 66 C20 but have not looked at that part yet..

[Captainfab]

If you get a '71-'72 12 bolt , make sure you get the panhard bar with it. The '65-'72 panhard bar is shorter than the one you have on your C20 now. The shorter one will work, but you will have to slightly bend it where it bolts to the frame bracket. This is because the frame bracket for the longer panhard bar is at a slightly different angle than for the shorter panhard bar.

As an option, the panhard bar bracket on the HO52 that is in your truck could be cut off and welded onto your new rear end.

[66coffin]

Originally Posted by Captainfab

If you get a '71-'72 12 bolt , make sure you get the panhard bar with it. The '65-'72 panhard bar is shorter than the one you have on your C20 now. The shorter one will work, but you will have to slightly bend it where it bolts to the frame bracket. This is because the frame bracket for the longer panhard bar is at a slightly different angle than for the shorter panhard bar.

As an option, the panhard bar bracket on the HO52 that is in your truck could be cut off and welded onto your new rear end.

if i do as you say and cut off the bracket from my rear end and use it on the 71-2, would that be better than using the c10 panhard? also, i have heard that a longer panhard is better for a lowered truck (which mine will be) why is that?
what is HO52? thanks.

[Captainfab]

A longer panhard bar is better in that there is less side to side movement of the differential as compared to a shorter panhard bar. So yes utilizing the one you have would be better than the shorter '65-'72 panhard bar. This is especially true on a lowered truck or one that has considerable suspension travel.

The HO52 is the designation for the 3/4 ton rear end that is currently under your truck.

Originally Posted by 66coffin

if i do as you say and cut off the bracket from my rear end and use it on the 71-2, would that be better than using the c10 panhard? also, i have heard that a longer panhard is better for a lowered truck (which mine will be) why is that?
what is HO52? thanks.