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Bruiser! 78 620 KC project


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The truck was sitting on the bump stops, no wonder the torsion bar adjustments  were not resulting in any ride height differences.




Out comes the reciprocating saw, and off comes the end of the bump stops:




This gave me the freedom to adjust the torsion bars as needed to level out the front end. 


The right and left adjusters were still different to each-other like when I started.  Kind of weird but what ever.  (would you say my tranny might need a new rear seal?)




Then it was on to the rear.



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I figured I should just start with trimming the bump stops from the beginning as it would be easiest with the wheels off so I didn't want to discover the problem after setting the truck down on the ground.




I see three dots, must be for a 3" drop right?!  :)




I've done a few 510 wagons so this end of the truck was pretty straight forward.






It's always a good idea to look around when you are working on your Datsun as sometimes you catch other things.  Like this driveshaft bolt that was not tight:




In with the blocks:





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FWIW, I've lifted 3 720s. Each one of them was like yours with mismatched lengths on the torsion bar bolts. I ended up learning to ignore that length and just measuring wheel arch height to level them.

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  • 2 weeks later...

I've been thinking about what's next and wouldn't you know, more power comes to mind?


I called my friend that build the RX7 LSD rear end in my 510 wagon to see what he thought about doing another one for the 620. 


In the process, I measured the width of the early and late 620 rear ends.


The early (up to 77?) rear end measures about 53 1/2" drum to drum




Sorry for the bad picture, it is still in Jeff's truck.


And the later 78/79 rear end measures approximately 54 1/2"





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This is a little unexpected as elsewhere on Ratsun 620 rear end measurements are as high as 56" and the difference between the two listed as much as 2 1/4".


However, someone else listed the 720 axle at 56 3/8" so maybe someone was confused?  Or maybe one of us measured wrong.


Either way, I need to determine the axle width I want for the modified RX7 rear...

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I also need to determine the right bolt pattern.


The RX7 rear hub/disks apparently aren't quite big enough for the stock 6 lug pattern.  The stock RX7 rear end is 4x114.3 so I could use that and then re-drill the stock front stuff to the same.  The cool thing about that is that I could run any of the wheels in my 510 selection.  However, there is a LOT more fender space in a 620 and I'm afraid 14" wheels with low profile tires would look a little lost in there so I'm leaning toward 5 lug, and 15" wheels.  I can get the RX7 rear set up with 5x114.3 and then convert the front to 720/hardbody spindles with toyota 5x114.3 hubs as per Mike Klotz.






I almost need to find those first and then build the rear axle to suit.


I've had this picture from the internet for years.  SSR F5 wheels.  Beautiful!  Now I might actually have a vehicle that I could run them on.




But then in the process of reasearching/shopping, I found that they make 5 lug versions of some of my other favorites:


Techno Racing or Super Star




SSR Star Shark








Work Ewing III




and even Watanabe (re-pops anyway)




It was was going to be difficult just enough to find a set.  Now I have to decide which ones I want too!

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So I take it you would be swapping the entire axle? Do you know the width of the RX7 axle, will you be modifying it to be the same width as the stock 620 axle? 


The RX7 axle is quite a bit wider.  I don't remember exactly how much but I have it written down.  I will edit this when I find it.  I will be narrowing it.  How much somewhat depends on the wheels I choose.

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I'm afraid it was the alternator, but more on that later...


But then the 2nd week in February...


The *new* rebuilt alternator died.  I found an old one in the garage that came with the tan parts truck.  It was a rebuild which I thought was odd since the truck had been off the road since '81 or whatever but I installed it and it worked like a charm straight away.


(left - old rebuilt alternator - right - *new* dead rebuilt alternator)



I drove to O'Reilly's to return the dead alternator along with the first alternator (core) that started this mess.  Also a core starter from Granny and a year's worth of oil to recycle.  The first guy at the counter was so thoroughly confused by what laid on the counter in front of him that after 15 minutes of looking through computer screens trying to figure out how to exchange the alternator, he gave up and asked if he could help the next customer.  Sure why not.  Then it was back to me, he recycled a couple gallons of my oil, then came back to the monitor and poked a few more keys, then he just left the store.  Not kidding.  And there were 3-4 others in line. 


I just stood off to the side for a bit and let the remaining counter guy take care of the other customers.  Then he came to me and picked up where the other guy left off.  Finally he handed me my replacement alternator and a receipt showing the exchange and a couple items I bought while I was there.  About 45 minutes after arriving I left the store and and got back in the truck.  I looked at the receipt and found that I was credited $7 for the alternator core - and charged a $7 core for the one they gave me in exchange!  All that time lost for a net zero gain.  Live and learn...


The replacement alternator sits in its box on my shelf now since the old one I found is still going strong.

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