C10 "69" six to five lugs rearend conversion

[profe56]

Hello everybody, I was lost for a little while but I'm here again to ask for your help, counseling and orientation.
Well: few months ago I did the drums to disc brake conversion then manual to auto tranny 700r4 conversion, now I'm on the way to change or upgrade the rearend in order to have five lugs and at the same time, decent rearend.
TEXAS FIRE suggest one from a suburban 3:73 I think but I want to know if can I use 73-87 rearend, welding The CPP Weld-on-axle seats If one of the members did this conversion can I see pictures.
Thank you so much

[profe56]

No one?

[chevy_mike]

Got to be patient, especially on weekends. Guys are out working on their projects.

To answer your question, yes you can use a 5 lug rear end from a '73-'87 C10. Just cut off all the old brackets/mounts and then setup your axle with the weld on pads. I did this myself and used measurement and pad angle from the original axle. Here are some pics.

'73 axle with mounts cut off and cleaned up



Centered the rear end and set the angles to match stock, snugged the U bolts enough to hold the angle until I could get the brackets tacked



After tacking, pulled the axle and fully welded the brackets



Painted up and new diff cover



BTW, since the newer rear ends don't have the boss cast in for the panhard bar, you either have to fab that up or use one of the adjustable panhard bar kits that move the axle mount to the control arm to axle mounting area. ECE and CPP both make these.

[profe56]

I think I was to much patient to say Thank you MIKE but I was very bussy working.
Mike with these pictures is very easy to understand what to do, now I'm looking for the rear end
THANK YOU AGAIN

[keanevann]

Where did you get the pads to weld on to the rear end???? Im looking to do the same....

[profe56]

CPP go to Classic Performance Parts and you see the cataloge, in the cataloge go to 67-62 chevy trucks and then look for rear end conversions
good luck.

[chevy_mike]

Got mine from Early Classics, when I ordered all my suspension parts. CPP works too.

Heck, I have thought about making a jig off my original rear end and offering to do the welding setup for local people (for a small fee) but just haven't ever found the time to do it.

[oldblue1968chevy]

Im really interested in this but not sure about getting everything lined back up....7387 is more popular than 6772 stuff round here..ive gotta 5 lug coil spring rear but i think its just a good core..

[Sammy]

July '10 CUSTOM CLASSIC TRUCKS get you a copy of that magazine. They have a complete article front and rear swap to 5 Lug. The rear axles tech article is how to remove yours and how to for low cost have your axles redrilled to 5 Lug page 88 with the correct spacing size studs template specs to give to the machinist. I haven't heard of a less hassle or cheaper conversion for the rear.

[88fordf150]

Or you can get a set of these that bolt right in your 6 lug 12 bolt rearend for $279.00 from Early Classic's

[Monte Carlo Man]

Why would you want to go to all that bother - when like F - 150 said, all you have to do is change the axles.

If you have a 12 bolt rear end, all you need is the axles out of another 12 bolt rear end. Probably the 70 - 72 axles on a half ton two wheel drive truck were 5 bolt. Then all you have to do is buy two new brake drums and 2 quarts of gear lube and a tube of blue goo and you can swap those axles in about a hour.

There is no benefit to swapping the whole rear assembly unless you were going to use leif springs.

Speedway motors sells kits that can be welded on to convert the drum brakes to disc.

[88fordf150]

Originally Posted by Monte Carlo Man

Why would you want to go to all that bother - when like F - 150 said, all you have to do is change the axles.

If you have a 12 bolt rear end, all you need is the axles out of another 12 bolt rear end. Probably the 70 - 72 axles on a half ton two wheel drive truck were 5 bolt. Then all you have to do is buy two new brake drums and 2 quarts of gear lube and a tube of blue goo and you can swap those axles in about a hour.

There is no benefit to swapping the whole rear assembly unless you were going to use leif springs.

Speedway motors sells kits that can be welded on to convert the drum brakes to disc.

The axle in the 70-72 aren't the same lenght, something like 1/2" difference. Thats why Early Classic sells these to fit right in, much easier way to go.

[gregg72340]

What about for us guys with leaf spring trucks that want to swap the bolt pattern in the rear is there anything that will bolt right in?

[AH619]

Originally Posted by 88fordf150

the axle in the 70-72 aren't the same lenght, something like 1/2" difference. Thats why early classic sells these to fit right in, much easier way to go.

no more than 1/4 inch each. I have swapped them and made a spacer out of 1/4 plate to space out the backing plate. Its cheaper than new drums.

[made2drag]

Originally Posted by Monte Carlo Man

Why would you want to go to all that bother - when like F - 150 said, all you have to do is change the axles.

If you have a 12 bolt rear end, all you need is the axles out of another 12 bolt rear end. Probably the 70 - 72 axles on a half ton two wheel drive truck were 5 bolt. Then all you have to do is buy two new brake drums and 2 quarts of gear lube and a tube of blue goo and you can swap those axles in about a hour.

There is no benefit to swapping the whole rear assembly unless you were going to use leif springs.

Speedway motors sells kits that can be welded on to convert the drum brakes to disc.

I know this is a super old thread but im swapping my 69 12 bolt to a 85 10 bolt because the 85 didn't need a carrier bearing and the 85 rear end complete was only $100. Every dollar counts sometimes. A $279 pair of axles is triple what a 73-87 rear is, most times. The 60-72 axle pads are like $40 on ebay. By the time I put a pinion bearing and brakes in the 69 and bought new axles, I would be in it about $500. Plus I will have all new 86 c10 stuff on a disc brake conversion up front. The 85 has 2 3/4 wide drums while the 69 was light duty. There's the benefit, for anyone reading.

[made2drag]

This is very cost effective swap and in my case, an upgrade. The 10 bolt 85 will still handle 400 hp and more.... so moving from 12 to 10 isn't a biggie for me.

[made2drag]

Chevy_Mike, well done on this how-to.... it is a great visual

[Tx Firefighter]

Another draw to using a 73-87 axle compared to converting an earlier unit with new shafts is that 73-87 units mostly had friendly highway gears. If your old 6 lug axle has 3.73s or lower, you're going to suffer on the highway without an overdrive trans. A 73-87 is easy to find in 3.08 or 3.40 ratios, or even 2.73 if you really like to stretch your legs on the highway.

[made2drag]

Originally Posted by Tx Firefighter

Another draw to using a 73-87 axle compared to converting an earlier unit with new shafts is that 73-87 units mostly had friendly highway gears. If your old 6 lug axle has 3.73s or lower, you're going to suffer on the highway without an overdrive trans. A 73-87 is easy to find in 3.08 or 3.40 ratios, or even 2.73 if you really like to stretch your legs on the highway.

Agree. I got lucky to be stuck with a 2.73 rear end. No one really wants one around here... im not into speed, just cruising...so its perfect for me.