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ONE MORE saved!!!! first datto


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Hello everyone!!!


I'm the proud parent of a new (to me) 72' 620, this is my first Datsun but my millionth import. I've been wanting a 510 for years and recently sold my truck to buy an S2000, that created a void of not having a vehicle with utility......then a light bulb went on, a 620 is like a 510 with a bed, and I do NEED a truck right? found this gem locally.



1972, the previous owner swapped in an L20b and a rebuilt 4 speed manual it also has dual carbs and an electric fuel pump and a Doug Thorley header. I am very hesitant about them because I am not familiar with carbs, it was running ok when I bought it, spent 6 hours today removing all cheesy stickers,prepped and painted on bedliner, replaced fuel filter cap rotor and spark plugs, also repaired a vacuum leak from a previously installed vacuum guage and replaced all fuel lines. Starts right up now! The idle is a little sketchy, the original single throttle cable is being used with a custom linkage to two carbs, There appears to be secondary valves which aren't in use


Sorry for the novel I'm just very excited


Can anyone ID these carbs?

any pointers on stabilizing the idle(about 1000-1200 rpm) or am I just used to injection and the roughness is in my head?

Is 2 1/2" header back to a straight through magnaflow overkill?


any other pointers?
















************************** NEW UPDATE ****************************************




just thought I would update the pics after a long day of working on her, I couldn't believe how much better the paint is now, just used a buffer and some coarse rubbing compound, also finished spraying the bed liner, painted and installed the front grille and gave her a wash, looks like a different truck! I really want to install the fender mirrors and paint the wheels black next.














thanks for looking!

Edited by Toasteee
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Welcome! Use the search function for su carbs. Nice truck. SU are great carbs once you learn them. Also fill out your location. You might have Ratsun people down the street and nobody will know without your location filled in.

Edited by Charlie69
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Its hard to say without better pics. There are the round top and the flat top variety. I think the round top are more desirable. Some guys love the SU carbs, others hate them. Its more a personal preference. GGzilla, another forum member, seems to know quite a bit about them. PM him for details or just wait for him to chime in.

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one thing I just remembered is the previous owner installed a fairlady cam when he rebuilt it, it does lope a bit but I like it. Every car I've ever owned has been turbocharged whether factory or custom, this one will be too. I'm still researching the ancient art of blow through turbo. Seems like the carb must be prepped and sealed and fuel pressure must be 3 to 1 ratio with boost pressure.


Does anybody know the breaking point of the factory rods/pistons? Will the L20 support 200whp stock if there is no detonation?:cool:

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Good score. The su's are awesome carbs and can be tuned much easier than you think. As far as smooth idle, look to the points (gap, timing,condenser,condition). Invest in a uni-syn, or piece of 5/8" hose for tuning them. You'll figure out the mixture easily enough. Remember, popping through the carbs is lean, backfires are rich. Always be sure the timing is right, it's easy to mistake carb trouble for ignition faults.

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  • 1 month later...

Just a little update....


Buffed out paint, painted front grill, hood and wheels semi-gloss black, also sprayed in bed liner, painted inside two lights yellow, also lowered 3" front and back, still need to lower another 1" or so in the front but it looks SO much better to me now. I've never had a car since my 90' eclipse GSX that I enjoy looking at so much this truck has so much character.


I also removed the huge mirrors and am considering fender mirrors if I can find the correct style. Also got a sweet Mooneyes heavy shift knob that I forgot to take pics of. Also picked up the front datsun emblem inside door handles and electronic dizzy at the DHM swapmeet/show today!






First Day I brought her home:











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yes the rear bumper is coming off next....but the hooks will probably stay because this truck is going to be used to haul stuff regularly, unless I can find a better option for some recessed hooks or something.


edit: I'll take pictures of everything I've used so far if anyone wants to duplicate anything, used basic buffing compound and an orbital buffer for the paint, some $9 / can bedliner, and stained glass paint for the headlights.

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Welcome to the family!

I like your truck, man. Nice score.


I came over from the import side too. Had to sell my 99ek (b20z swap w/ Si tranny) because too many kids wanted to steal it, and I got too many tickets with that thing.

Driving an old datsun is way cooler. Every time I come out and see it parked, I cant help but smile at it.

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