Earlier this year I 3 linked the 80. I was mostly procrastinating but taking the time to drive it around has giving me some pretty good insight on the pros, cons, and compromises you make when you link a car yourself. I really want to make this pretty comprehensive, I had so many questions that I couldn't find any good info on and it's super frustrating. So I'm going to try to go into everything from how to use the calculators, which one to use, what products to get, what to worry about, and much more. I will preface this with, I'm not a genius, I'm just a dude who linked one car, there's thousands of people who know better than me, but everything that I'm going to talk about is stuff that I've either experienced or learned from someone who has. Everybody thinks they know alot about suspension, but this project has taught me that I really don't. This is a bottomless pit of stuff to learn that is largely useless. Here are my thoughts.
I should start with why you would 3 link a car. I talked to alot of people before I did it and I was told that the car was going to suddenly become undrivable because its 3 linked. Can it? Totally, there sooooo many ways to screw this up, but my biggest take-away is that the drivability of the car is largely attributed to the geometry of your link set up (duh), your shock tuning (less of a duh), and to some degree your tolerance for an unwieldy car.
Reason 1* Design it for your ride height
It doesn't matter if its a radius arm, 4 link, 3 link, IFS, or leaf sprung, every OEM manufacture designs the suspension to operate within certain parameters. When you lift or lower a car, you venture away from the angles that the suspension was designed to operate at (this is often called the suspension geometry). Ie, when you lift an 80, the angles of the radius arms, and 4 link in the rear become steeper, this results in adverse driving characteristics that we either deal with, or mask with aftermarket parts.
When you link a car, you have the opportunity to design your suspension for your desired ride height. You can do this by taking a ton of measurements and throwing them into a link calculator. I recommend the one on irate4x4 because it gives you alot more information than the old triaged calculator that you can find on crawlpedia, that one's fine, but it was made for the rear suspension of drag cars. I'll get more into how to use the calculators later. Do you need to use a calculator? No, there's lots of rules of thumbs that will get you close, but this is a lot of work and I like to have something suggest to me that it will be drivable on the road, soooo I opted into using a calculator.
Reason 2- Tune-ability
Especially on this forum, people don't... like to stray away from the norm. Most people overspring their cars, yes... if you put a 3" lift spring on your car and get 5"s of lift out of it.. its over sprung... no it does not make it more stable or make it ride good. This is a common trend though for most Toyota's, I have a weird feeling that it come from Australian touring set ups that required such heavy springs but whatever. ANYWAY more often than not, people opt for heavier springs than needed and it results in very little body roll on the street and a very poor ride that most just deal with. In total, I've had 3 old man emu lift kits, 2 Dobinsons' lift kits, an old man emu rear / custom spring lift kit with dobinsons' yellows, and now a fox coilover/ air bumbs front, icon spring rear spring with Dobinson MRA set up. I will say, that without a doubt, every suspension kit that I have used until now has ridden HORRIBLY. So when people tell me that their XYZ lift kit rides well, I know that they don't know what they're talking about. Suspension NEEDS to be tuned to ride well and twin tubes/ foam cell shocks will not ride well.
3 linking your car gives you a good opportunity to run coilovers. Coilovers are not inherently special, but they give you the ability to tune your suspension. There is a near limitless combo of shock valving/ spring combo. If you can't find a combo that works, you should get rid of your car. If I didn't go this route, I would've opted for a set of custom valved shocks from Fox with a dual speed compression clickers, or set of Dobinsons' MRAs front and rear. The clickers give you the ability to adjust the fluid restriction going into the reservoir with a low speed and high speed circuit. Oh and the MRAs allow you to adjust rebound through bleed. I'll go into shock tuning basics more later. BUT its very nice to have a car that doesn't rattle your teeth out.
Reason 3* You have suspension that's designed to live through what you want to do.
No you don't need to link your car to hit the rough stuff. But I promise you that the universal parts available to you are far more robust than the parts designed for a car that was orginally on 31" tires. The radial static load of a 1 1/4" heim is 76,000 lbs, please find me a bushing that can compare. Need I say anymore?
The biggest thing that you need to consider before taking on a project like this is....... DO YOU NEED IT. If you want to go to moab and hit hells revenge.. absolutely not. Do you do the rubicon and not hit soup bowl? Definitely don't need it. I did it because I wanted to hit 9 and 10 rated trails, I was tired of my 80 chewing through bushings, and I like building stuff because I think its cool.