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Discussion Starter · #1 ·
There is a guy in my town with a CJ7 and 1 ton Chevy full width axles under his CJ7 with 39.5 inch Boggers.
What mods are needed to do this swap in the front?
The rear I can take care of, besides the brake lines and e-brake cable I need to grind off the original spring perches and move them to the proper location on the axle.
BUT should I use the Jeep or Chevy spring perches?
I would imagine the Chevy perches because of the axle diameter on the Chevy axles.
On the front axle what steering mods will I need? Tie rod or ?
Anyone done this modification? I have a 1975 Jeep CJ5 with the 304/T18/
ALSO: Should I use Jeep or Chevy Springs? Anyone out there have or had exeperience with the Revolver Shackles and/or MonoLeaf lift springs.
How much do these run?
 
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Discussion Starter · #2 ·
On the front you will need to move the spring hangers outboard, mine were moved out 2". Use perches that fit the Chevy axle. I am going to use a cross over steering setup. Here are some pics of the brackets that i copied from Jeepn on this board. High5 and Elusive also gave some input. If you run into trouble these guys can bail you out.

 

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Discussion Starter · #3 ·
Thanks. By outboard you mean? inward? or on the outside of the frame? did you have to do this on both spring mounts in the fron on each side?

1975 Jeep CJ 5 - 304 - T18 4 speed
 
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Discussion Starter · #4 ·
The mounts have to be moved outside the frame, to accept the wider Chevy axles. Yes you must do this to the front and rear mounts for the front springs. Here is another pic that show the mounts (the frame is upside down, for welding).

 

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the front chevy dana 60 has one perch already cast into the housing.. its really hard to move, so outboard the perches. i didn'ty have to with my wider frame. it's a good swap.. you'll never break anything or need to upgrade again. the axles are very wide though.. if i had normal rims, my jeep would no longer fit on my trailer.. and it's illegal in most states to hang out that far.

~~Elusive~~
/wwwthreads_images/icons/tongue.giftj-7..tellico tested, uwharrie /wwwthreads_images/icons/tongue.gifsafaried..1 ton drivetrain/wwwthreads_images/icons/tongue.gif..see it at http://www.jeepgod.net
oh yeah, and a 2000 tj,lift..etc
 

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<snip>I have a 1975 Jeep CJ5 with the 304/T18/</snip>

I may be wrong but I'm pretty sure the '75 frame is not boxed and very flexly. I think your looking at alot of work to put these axels on that frame. The one ton axels weight is about 3 times the stock axel and this unsprung weight will rip that unreinforced frame in two after you get a few miles on it. You can either reinforce the '75 (after disassembling to bare frame)or find a '76 or newer frame (already boxed)to start with. This may be something you might want to thing about.

I used a steering arm from Avalanche Engn that bolts to the top of the right side Knuckle for a crossover steering setup, very nice and easy.

Use springs with a spring weight rating for the weight of the front and back of your '5. Using longer springs will also give a softer ride, I'm using Alcan SOA spring on the front that are 5" longer then stock and I also moved the axel forward 2 1/2" to increase wheelbase(rear axel moved back 1 3/4") which helps the ride too. Your replacing all the hangers anyway so you can put them in a different place. If you do this, Think it out very carefully and measure many times before you weld or it will never track right.

Wayne in Hawaii
"PYRO" '77CJ5,350,T18a,FrontSOADana60,
Rear1/4EllipFF14bolt,'Glasstub,Warn8274,
37"Goodyear M/T,,,,,,,
 

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hmm good point... but the 76 frame isn't boxed either...
if you use angle iron like the front of the jeeps shown.. it will be plenty strong.. but the back may need a little extra reinforcement too.. cj frames arent very good even when they are boxed, but they can be made strong enough with plenty of angle iron

~~Elusive~~
/wwwthreads_images/icons/tongue.giftj-7..tellico tested, uwharrie /wwwthreads_images/icons/tongue.gifsafaried..1 ton drivetrain/wwwthreads_images/icons/tongue.gif..see it at http://www.jeepgod.net
oh yeah, and a 2000 tj,lift..etc
 

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I have two 76 frames in in my spares pile and their both boxed along with the '77 under PYRO. You are correct about reinforcing, my '5 has 1/4" plate steel welded to the outside running from the front of the frame to the frist body mount and the same on the top of the frame. All the front hangers are welded to these.

Wayne in Hawaii
"PYRO" '77CJ5,350,T18a,FrontSOADana60,
Rear1/4EllipFF14bolt,'Glasstub,Warn8274,
37"Goodyear M/T,,,,,,,
 

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the ends of the 76 frames are not boxed.. the last 10" or so front and rear. if your are.. they were either boxed, or they arent 76 frames... unless cj-5 frames are different than cj-7 frames...could be too..

~~Elusive~~
/wwwthreads_images/icons/tongue.giftj-7..tellico tested, uwharrie /wwwthreads_images/icons/tongue.gifsafaried..1 ton drivetrain/wwwthreads_images/icons/tongue.gif..see it at http://www.jeepgod.net
oh yeah, and a 2000 tj,lift..etc
 

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Went out and looked at the '76 frames and their boxed from the front cross member be the rear spring hanger, about 3 1/2' in the back is only C-channel. Thank you for correcting me. The '77 frame under PYRO was boxed from the front cross member to the rear of the frame at the factory.(I removed the front crossmember, boxed this area and made a stronger crossmember to mount the winch .) So Now, I think the '77 would be better then the '75 but I could be wrong :)

Wayne in Hawaii
"PYRO" '77CJ5,350,T18a,FrontSOADana60,
Rear1/4EllipFF14bolt,'Glasstub,Warn8274,
37"Goodyear M/T,,,,,,,
 
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Discussion Starter · #11 ·
I'm just reading along and wondering if I should do something different with my frame? I've got a '73 CJ5 and It's all apart, right now. I've been looking at the frame and wondering if I want to use it or not? I've also got a '71 commando and was reading on Parts & Pieces buildup, that he used a commando frame under a CJ3B, because it was so strong, best frame made in a CJ width vehicle, according to JP magazine. Rated at 53,000 lbs. bending moment, compared to 35,000 lbs for a '77 CJ. I'm relying on memory for the numbers, but upon request I can quote them from the artical, I don't have it here at work. I can get a commando frame in 20 minutes, from a local parts source. Or I can box my frame, Or I can leave it the way it is, not fully boxed.
I'm sure I'm not ready to fork out 2200.00 for a new frame, so what should I do? What would you do?
Thanks, Devin

 
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Discussion Starter · #12 ·
Here's another thing to consider with the '75. The width of the springs is 1-3/4". The spring perches for the Chevy axle are probably for a 2-1/2" spring. If you are going to outboard your spring hangers you should consider using a different set of springs. I'm boxing and building a new frame setup for my '75 right now and I am going to use Wrangler springs with a couple extra leaves in a spring-over axle configuration. Right now I'm still trying to decide what width that I want my axles to be. Luckily I have an extra frame so my downtime should be small.

'75 CJ5,258 w/Howell EFI,T18a,4.27's,33's,On-board air,Warn 8274
 

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My neighbor works with a guy that has an old cj5?cj2? with full size chevy axles from a 1/2 ton on his jeep. The jeep is street legal as far as lights and safety stuff, but the tires, about 35" boggers are completely outside of the jeep body. The jeep has been stripped of all unneccisary weight, is running a built chevy small block with auto, and is used for competing in mud bogs. I have never spoken to this guy, but my neighbor claims this jeep is very fast. In the 1/8 mile drags, it is one of the faster vehicles to run. He does not do any other thing than mud bogs with it except drive it around town sometimes.

Enjoying Montana's Big Sky & Snow(Skiing that is)
 

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There is a guy in my town with a CJ7 and 1 ton Chevy full width axles under his CJ7 with 39.5 inch Boggers.
What mods are needed to do this swap in the front?
The rear I can take care of, besides the brake lines and e-brake cable I need to grind off the original spring perches and move them to the proper location on the axle.
BUT should I use the Jeep or Chevy spring perches?
I would imagine the Chevy perches because of the axle diameter on the Chevy axles.
On the front axle what steering mods will I need? Tie rod or ?
Anyone done this modification? I have a 1975 Jeep CJ5 with the 304/T18/
ALSO: Should I use Jeep or Chevy Springs? Anyone out there have or had exeperience with the Revolver Shackles and/or MonoLeaf lift springs.
How much do these run?
 
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