Functional Differences Between 1956-57 And 70-71

Yeah I'd be surprised if you could get up to 60 without a long run. The interstates arrived with Eisenhower, and I don't think highway speeds would be expected. Boulevard speeds. People still traveled long distance by rail - station wagons carried the guests and bags from the station to the resort hotel and back.

The flanged axle may have a different GAWR than the earlier tapered axle. This is the only functional difference that I can think of. Pretty sure the loading will be limited by the bearing lifespan. My opinion is that's what happens when you load 20 bags of Quik-Crete in the back of your Jeep and expect it to not hurt something. Overload it and one of the axle bearings will fail.

 

flat head engine will develop more than 100 hp. You raise the horsepower by raising the compression ratio, which is a lot easier to do with a flat-head over an F-head.

 

I shaved a solid .125" off an F-head head as an experiment to see how far I could go without hitting water jackets. It worked out to around 10:1 compression. Strong runner with a 2bbl until I cooked it.

 

From this discussion the flat-head went the way of the DoDo because of hi-octane gas.
With the octane level of current fuels, maybe the auto manufacturers should consider re-introducing the flat-head engines. They are better suited to the lowering level of fuel octane.

 

My rear axle is the 70 1/2 to 71 30 Spline Flanged currently with an Eaton E Locker G2 5.38 gears and all SKF Bearings and Seals Set up by one of the most respected 4WD Chassis shops in this part of Oregon so I have no doubt it will do as it was intended when new. The only parts reused in the Axle assembly was the housing, the shafts (which were near perfect condition) and the cover. Even all nuts and bolts are new Grade 8's Everything in both front and rear Brakes is new except the backing plates.

Here is a photo of the rear of the frame showing the New 2" receiver and its support structures





You see bolts holding the center of the 1/4" thick Shackles to 3/4" thick block in the middle They are also fully welded in place I just figured the Bolts were a safety back up. The 9/16" and 7/16" Pivot bolts are core drilled and grease-able The uppers pivot in Bronze bushings.



disregard the air tank its no longer part of the program.



Something to note the bolts holding the brackets to the frame ends are not through bolts but have Nuts or the bolts come from the inside so there is no crushing of the tube and twice as many sheer points with 8) grade 8 3/8" bolts on each side. The section of 2x2 tubing you see is thick wall same stuff used to make a stinger. As you can see the rear cross member is now a Tube rather then a channel and is 3/16" thick.

The unusual Shackle mounts are machined solid 1020 steel that were used to keep the Shackle pivot point in the stock CJ-5 position when the rear frame was cut down 2.5" to match the shorter CJ-2A tub. It retains the 81" WB as well. The boxing plates are also 1020 steel and 1/4" thick.

As to the Interstates having something to do with the speed people drove back in the day. Oregon only has two Interstates even now one North South and then the East West along the Columbia River.

I'm not sure where you are from but the farmers and their wives where I grew up were doing 75-80 on the two lane state Hwy in front of our house here in Oregon in the 50's-60's and until 1975 when the speed was dropped then they were only doing 65-70. I remember going to pick strawberries in the J-3000 Gladiator Pickup and mom catching air going over the railroad tracks at 80. Or being brought home from Cub Scouts by the neighbor gal on 2 lane county roads at close to 100mph in their Impala.

SAFE? no but I can only remember one fatal accident in our area and that was when a Milk truck pulled out in front of a car load of kids headed to High school one morning. There just weren't enough people to have more accidents. Different now since everyone and their cousin moved to Oregon.

 

Was that responding to me? I'm not sure what your point is. The flanged axle is different from the tapered axle. They will have a GAWR gross axle weight rating. It's irrelevant who set it up or what brand of bearings were used. Axles have a weight rating.

You asked for design differences between the years. That's an obvious difference.

 

think that one is on me, Tim, with my comments about farmers not hauling their trailers very fast.

 

Of course there are differences between the years.
Just an FYI.
In my neck of the woods V8 powered 2As,3As,3Bs, and CJ5s were all pulling 15-20 foot house trailers
to weekend Jeep club outings routinely in the 60s and 70s.

Did they have upgraded brakes and steering....of course.

You are over engineering and over thinking what you want to do.

 

Yes timgr my response was based on your comments. I was not disagreeing with your comment about the GAWR of the rear axles Only informing the thread about what my rear axle and suspension is currently made up of.

They used the Dana 44 in the MJ's with a 2200lb load rating. in 87-92 the same basic 30 spline version as what I have. .

 

Just curious... was the GVWR for the 5 the same as the 6? Was it strictly based on limits of components used? Or was the added safety of the 6's extra wheelbase taken into consideration?

Or, if the GVWRs were the same, wouldn't that essentially make the 6's towing/carrying capacities a little lower in comparison due to the added curb weight of the longer 6?

 

I don't really believe that there is a big difference between the 56 and the 71, except that I have the fuel tank at the rear and drums are a little big bigger or less smaller.

I use sometimes my CJ5 to bring wastes to the waste deposit, and I don't go fast... I would't take the risk of driving my CJ5 with something heavy at the rear to be pushed away in the curbs, but it is probably funny, sport.
I wish you good luck!

 

Short answer "No".
The '70-'71 had better brakes, and a different D44 rear axle. Everything else remained the same. Unless you bought one that came factory with a V6. Then your towing capacity went up some.

 

There's no real diff. that you will feel.
If your building an early Cj5 for towing or driving, The best thing you can do is get one with a buick v6. I have both, there's no comparison as far as driving. I like my 4cyl in my flatty because it's original and simple. but that's it. My v6 in my early cj5 or my 3b actually makes it fun to take for a drive. It has fantastic torque and good power, simple to maintain etc. It doesn't over tax the drive train. Go 4:27 gears. OR ideally a fordT18 4 speed, v6, overdrive, and 5:38 gears. Add 11" drums in the rear, and either disk brakes or 11" drums up front. I've run this for years and It's fantastic.

 

Forgot. The wipers are at the bottom of the windshield, are they not?
That makes a big difference on your sight picture through the windshield.