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SVO 620

Idaho Hillbilly

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Hey all, been on and off the forums for years. I've now acquired a total of 3 620's and finally have one that I'm actually planning to build. Picked it up several months back and parked it in the corner of the shop. Ordered my first batch of parts for it last week and just finally decided to see if I could make her go. Supposedly was in storage for at least 10 years before I picked it up (out of the storage unit). Has a Detroit locker in the rear, a completely rust free body (literally have not found ANY), L20b with a cam (supposedly) and Mikuni 44's.


First batch of parts was a little random, but I picked up front and rear window seals, full engine gasket set, spark plugs, timing set, brake master cylinder, clutch master cylinder and slave cylinder. 


I was told that it had a blown head gasket when I bought it, but thought the first thing i'd do is see if I could get it fired up and test that out for myself. Did a quick swap of the fluids, ran a dedicated fuel line to a gas can with new fuel, threw the new plugs in it and started cranking. To my surprise, it took off pretty quick, but idled quite rough. Give it some throttle and it smooths out and actually revs quite well. Started pulling plugs one at a time to determine the cylinders that were not firing. I found that I could removed both plug wires for cylinders 1 & 2 and have no change in engine operation... bummer, blown gasket between one and two?! Removed plugs and performed compression test on both cylinders... 175psi in #1 and about 160 in #2... huh, well maybe they have the firing order off? verified that it was correct at 1324. Verified that the front carb is fueling (it is). 


This is where I currently sit. I am kind of thinking that the front carb is actually over fueling to the point that I have a dead miss on those cylinders? On that topic, I'm sure that these carbs could use a solid rebuild. I don't know anything about them... what is the best option for having them rebuilt? 

​Pics below of what I'm working with! Looking forward to the build with you guys  :)







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Multiple carbs are super finicky in regards to being sync'd at idle. As in they all need to be identical in their throttle position or they will idle like crab, higher up in revs they tend to be less intolerant. Make sure the linkage is adjusted correctly, try removing the centre link between the carbs so they are independent of the other pair of cyls. See if idle improves. If so more work is needed on your linkage adjustments.


Set both carbs to the same idle screw setting. A carb sync tool makes checking easier. Google 'best lean idle' it will help,i saw a sticky in the engine section for setting webers it is the same over all process for mikunis.


Check the entire ignition system, check your initial advance i ran mine somewhere around 14 degrees for mikunis from memory.

Eventually once running you will need to establish the advance curve, about 32 degrees worked for mine all in around 3000rpm. Vac advance may or may not work depending on a bunch of things.


Ignition is half the issues with ir carbs, throttle linkages is the other half. Get them right first.


Fuel pressure needs to ne about 4psi max.


Hope that helps a bit.

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Oh yeah depending on linkage set up you can twist the throttle shaft and have one throttle plate slightly open more than the other on the same carb. I ran stops adjusted so that both plates are supported and no twist can occur between throttle bores.


Get rid of any vacuum leaks too. That will ruin your week.

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Thanks guys. I'll double check the timing to make sure I had them in the proper order. Pretty sure I just typo'd above, but I'll take a look. It also appears that I need to host the photos somewhere else...


I've never seen a cylinder over fuel so bad that it would not fire at all, but I can unplug 1&2 independently or at the same time and have zero change to the engine.

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Yea, try Postimage, Photolame ruined millions of photos on forums and the like all over the world, one would hope that place was history, but they are still around to screw with normal people.

I am surprised it will even run on 2 cylinders at all, the engine would likely be running really rough.

Maybe it is getting too much fuel in #1 and #2 and flooding out.

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  • 2 weeks later...

Haven't been able to get back to the truck yet. Big snow storms, Christmas and too busy in the shop. I'll toy with it more after the new year hopefully so I can give some updates. Hoping to see how it runs with these carbs on it. Not really sure I like the filterless system where I live. I'll have to figure something out there or swap it all out for another setup. 

​Picked the whole truck up for $1200, figured the carbs were worth 2/3 of that anyways. The locker is pretty cool too, and where I live, a rust free body is priceless. 

​In the meantime, here's Ol' Red hiding behind a snow berm.



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  • 1 year later...

Looking for other peoples thoughts real quick... Should i stick with this frame and chassis and convert over to disc in the front keeping the kingpin suspension or should I swap everything over to a disc brake chassis I already have as well? My thoughts are that the stock disc brake parts seem to be getting harder and harder to source but I'd rather have the ball joint style control arms?! If I'm looking to go with coil overs in the future will it even matter?! 

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33 minutes ago, datzenmike said:

Switch to ball joint front end. The stock hub, rotors and calipers can be replaced with easier to source '83 and up 720 or D21 Hardbody vented rotors and larger calipers. 

Thanks for the input Mike. That's basically the way I've been leaning, Just needed some convincing to do the extra work 😄 

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Alright. You'll notice I renamed the thread to more accurately represent the project. Made a little progress getting the cab cleaned up and ready for removal. I plan to still pull the dash and and go back together from scratch. After I get the body off, I'll bring the other truck in and start striping it down to the chassis for the the swap. Since It's all about PICS though... work I got done this last week.


What the interior looked like to start with





The bed is solid and clean




The aftermarket gauge setup that was in the truck when I picked it up.










Passenger floor boards were the worst spot by far. Nothing actually through the floor which is an absolute miracle in this area. You can feel the integrity of this floorboard is definitely weaker compared to the drivers side. I'll get it all wire wheeled clean and see what I'm going to do with it. At this point, I think it will probably be fine after some clean up and new flooring on top and whatever I end up doing underneath. 





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Won my fantasy football league and took home some $ to spend.... so I bought myself a Christmas present! Excited to try these out. I'm normally a name brand guy when I comes to this stuff and had my sights set on a Digital Designs 8" sub originally. A buddy talked me into giving these a shot. Reviews are all excellent and the price is almost unbeatable. I'll follow up with a review at whatever point I get to actually play them.


Edited by Idaho Hillbilly
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Some more work done today. Interior gutted as far as I'm going for now.



Got the fenders and all the rest of the front components stripped.







Found this area where it looks like there was some damage before. The core support is also a replacement and has some failing tack welds that someone put in.




Got the cab off the chassis and set on some pallets




Got the bed off and the donor truck in the shop as well.




A few shots of the donor truck. I'll be taking the best from both to complete the project. The more I looked at this one, the more I'm considering just cutting the floor pan out of the gray truck... I just don't know yet. Gray truck has a lot more dings/dents than I had really noticed before. Red truck is pretty straight on the outside but the floors are rotted terrible.







Had some cute help for a little bit today too!




A little look at part of my old gas can collection. There's a Datsun piece in there if you look close (don't mind the mess, it's normally much more tidy). 




Probably wont get much more done until after the new year now. I'll make a final decision about which body to use and go from there!





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  • 3 weeks later...

Idaho Hillbilly, I'm assuming the very first picture in your last post is of the interior of the cab you plan to eventually scrap. That picture is a great big help to me as it helps me compare cabs with the one I bought for parts and practice. The one I got has a very rusty floor, with several holes through it,  so I don't mind using it for parts or practice. Time will tell if it has all the parts I need.



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On 1/10/2020 at 2:04 PM, MattSheldon said:

Great progress thus far! Let me know if you have a cab or bed that you are going to scrap

Thank you. Hopefully more coming soon as long as the temps warm up a little like they're forecasting at the end of the week! Red cab will be available for sure (although it does have some floor rot) along with whichever fenders I do not use. One of the beds may also be available... contemplating a matching trailer though.... so we'll see 😄



On 1/10/2020 at 6:43 PM, 620slodat said:

Idaho Hillbilly, I'm assuming the very first picture in your last post is of the interior of the cab you plan to eventually scrap. That picture is a great big help to me as it helps me compare cabs with the one I bought for parts and practice. The one I got has a very rusty floor, with several holes through it,  so I don't mind using it for parts or practice. Time will tell if it has all the parts I need.



Yes, that is the cab I will be finishing with. It will need a rocker panel replaced and a few misc. holes people have drilled taken care of, but it is overall the better choice.

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Beebani1028 on ebay, also a ratsun member makes a parallel 4 link ....

If you want to keep your stock gas tank that wont work....

He also make a 3 link with a watts link making it a 5 link.... uses the front factory leaf spring bracket....

My 5 link setup is currently being fabricated... 

Edited by Crashtd420
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