3 LINK REAR SETUP
Haven't designed or built it yet.
So looking for basic dimensions of the lower arms and info
Having designed one myself, one thing you'll want to look at is the length of the lower links compared to the length of the 3rd/upper link. you want that upper 3rd link length to as close to equal in length as possible. Reason is that the shorter that upper link is compared to the lower links length, the more the pinion angle will change as the suspension travels. Also, 3 link systems almost always result in the loss of the rear seat due to having to be mounted high up on the rear end, usually on the center housing. Now you can offset or angle mount one to help with that and you can try mounting it behind the axle center line to help with that length issue. Just food for thought.
Another thing to think about is will a parallel 4 link work for you? This would let you keep the rear seat and still give you better articulation than a leaf sprung system and better control over your instant center as well as rear roll center. It wouldn't articulate near as much as a 3 link system however.
Lastly, what device are you planning to use to locate the rear? Either a panhard bar or a Watt's link will work. I'm running a Watts set up in my Dart. No track time yet for results/reviews yet.
Also, I agree with Denny, that 3rd link welded to the sheet metal is a terrible idea. Not only that, it's FAR too short and will result in some very radical changes as the suspension travels. That thing cant be more than 6-8 inches long compared to probably 20-24 inch long lowers. Ideally, you want the upper links to be no shorter than 60% on a 3rd link, preferably 75% of the lower length. Example: if your lower links are 20 inches long, you'd want a upper link to be ideally 15 inches or longer with a minimum length of 12 inches. Also, those square tubing lower links are going to cause some issues as well. Go with round tubing and thread it so you can adjust the suspension, you'll want too. 3 links are supposed to be adjustable, those two pics from Fquick.com show a set up that is going to be problematic to say the least.
