1982 720 KC 4x4 differential question

[720trail4x4]

I have an 82 4wd 720 with the HF43 axle code which means I have an H190A rear differential with 4.375 gears but what is my front differential type? I cannot find this info anywhere. Thanks for the help. And what does the "A" designate?

 

 

 

I also have an 84 720 parts truck with the CA41 which I found means CA200 front and I believe an R180 front and that's a 4.11 ratio. Correct me if I'm wrong. 

 

 

 

Probably gonna put the 82 body on the 84 frame for the better front suspension, are the front diffs interchangeable? I realize that I have to match gear ratios but just wondering if it's possible as I probably want to keep the taller gears in the H190A. Thanks for the help!

[datzenmike]

The '82 front differential is an R-180 similar to the Z cars.

 

'A' I don't know. Maybe the case material. Early cars and trucks were aluminum then switched to cast iron? then steel. My 710 is ab H-165B

 

H type have the  gears mounted on a removable bolt in center section.

C are a Salisbury type where the gears mount directly into the rear axle through a cover plate on the back.

R do not have solid axles but drive the wheels through short bolt on dive shafts. Used on IRS cars

 

From '83 on, the predominant axle ratio is a 4.11. The rear axle was changed from H-190 to C200 because of the larger displacement Z24 engine.

 

I don't know if the '84 suspension is 'better' or not, it's different, but it does have much better upgraded disc brakes with a larger caliper and vented rotors replacing the earlier solid pie plate rotors. Might be easier to just swap the '84 brakes onto the '82. You'll want the '84 15/16" master cylinder with it. Up to you. If swapping the body I would keep the 4.11 drive train unless it's a working truck or you hunt.

 

 

[720trail4x4]

Datzenmike, always quick with the answers. Ha. Thanks for the reply. The desired end result is to have a little trail/snow trail truck with some decent tires, maybe 31s or 33s, a 9500lb winch (already have), the alternator/welder modification would be super cool, and CO2 air tank tire filling set up (already have) and with the front end setup on the 82 (torque arms mounted on the front of the lower control arm/torsion bars in their usual place) 84 has the heavier lowers and the upper control arm is mounted lower on the frame as opposed to the 82 mounted on the top of the frame rail. I came across a deal on a set of 31s but they rub the front cab corners quite easily. I realize I can crank the torsion bars but may just "clearance" the cab corners as there is a small half dollar sized hole in the floorboard on the driver's side. Thinking cut it out and replace it with a piece of floorpan steel with enough clearance for what suspension articulation may be available. 

 

       I live in Colorado at altitude and currently drive the 82 with a Weber 32/36 Dgev and my concern is that the slightly shorter 4.11s will kill what power is available from the z22. I do have a good z24 from the 84 donor truck that I plan to freshen up and maybe add a small turbo down the road. (That's another whole ordeal with the carb. Blow Thru or Draw Thru?) Not to mention that the Weber probably won't flow enough CFM to support the turbo. That's probably a year or so away. 

 

I got the 82 for free (was sitting for 12 years) and bought the 84 for $300 (minus one front fender and the radiator support as it was used to fix another 720). I replaced the carb, used the fuel tank from the 84 and plan on using the extra running gear (diffs, trans, t-fer case and motor) as spares. 

 

   Sorry that was long winded as I'm sure you know these things can get at times. Thanks again for your quick responses and your undying love for these Datsuns!

[thisismatt]

Fronts are R180. I can't remember if much, if anything, changed over the years. Early might be bolt-in stub shafts, later clip-in (cir-clips). No big change between the two other than the side gears in the diff having the accompanying threaded pieces for the bolt-in subs, or not. Pinion flanges may be different? Either way, shouldn't be an issue to exchange them.

[Stoffregen Motorsports]

From datsun1200.com

 

http://datsun1200.com/modules/mediawiki/index.php?title=H190

 

[datzenmike]

Maximum tire size on the 720 is 29" tall with very minor rub bouncing on turns. Anything different you'll need body and suspension lift. If the 720 had a solid axle that would be no problem but it's constrained by being IFS and torsion bars.

 

The '83 and up also don't have tension rods instead they have, for want of a better word, compression rods behind the LCA, These might also limit the lift.

 

Any taller tire will affect the overall differential ratio. Right now you have 27.7" tall tires and a 4.375 differential ratio. If you go to 33" it would be the same as swapping to a 3.672 differential, way worse than a 4.11. I would skip the 33s and just get a deep tread tire that is wider if you are off road. Stock is 215/75R15 which are 8.5" wide. A 265/65R15 is 27.54" tall and just under 2" wider at 10.4". Your crawl ratio and speedometer reading remain unchanged and you are not in the sky top heavy..