Thread: 4 Link vs. Multi-leaf

Tweet

I have a 68 Camaro with a 406 SBC built for torque (500+ ft/lbs). I have gone through the car and the last stage is the rear suspension. I have to replace EVERYTHING because the previous owner used air shocks with a mono leaf. I have been told that a 4 link rear hooks up off the line better than anything but it tries to bind up in corners. This car is street driven alot but I am building it to preform when the weekend rolls around. I want the maximum traction but still keep it streetable.
Justin' hopin' someones done it and can give some advice!

No bind w/a 4 link. GM & Ford used it for yrs.

Wow! What a can of worms... A "triangulated" four-link similar to what GM and Ford used will work on the street even with Heim ends. This is one of the most popular types of rear set-ups used by street rodders because it requires no panhard bar, eliminates binding, and provides a very good ride and good handling. Several pro shops use them, kits are available, or you can make your own, but... If you are going to flog this beast at the drag strip on weekends, this is not the set-up you want.

Pro Stock drag cars use unequal length parallel four-bar systems. This system uses bars that, when viewed from above, are parallel from side to side. When viewed from the side, the top and bottom bars are not the same length and are usually not parallel with each other. These are great for straight-line acceleration because by adjusting the mounting points of the links (they usually have multiple mounting holes) the "instant center" can be moved up or down which changes the amount of weight transfer that takes place under acceleration. These systems, however, are not good for the street because they bind terribly whenever the car tries to lean over in a corner. Eventually the brackets, the bars, or the rear axle housing will fatigue and fail.

You could use a parallel four-bar system with all four links the same length. In this system all the bars are parallel to each other whether viewed from top or side. This is the easiest of the four-bar systems to set up, but it provides absolutely no lift whatsoever under acceleration. It holds the rear axle in a neutral attitude regardless of its travel up or down. This system probably will not put those 500 ft-lbs of torque to the ground very well.

You could use a sort of "hybrid mix" of these two systems. Make a standard parallel system with all four bars the same length, but with multiple mounting holes. You could then adjust the mounting points of the bars to give you good "bite" when you go to the strip. Just make sure when you hit the street that all the bars are in a parallel attitude.

Your simplest, easiest, and least expensive option would be to stick with the leaf springs and put some "slapper" style traction bars under them. Lift is adjused by changing the snubber height and experimenting with the length of the leaves in the springs. With this system you don't have to crawl under the car and change a bunch of stuff every time you want to go to the races; it's always ready.

Tech Inspect - You are absolutly correct. You have to use stk rubber bushings or you will get binding........Don

theres good and bad with both set ups. ive done a few superstock drag cars on the west coast we used leaf springs with a either comp engineering or a caltrac bar. camaros are easy theres two ways to go for leaf springs mono with the bars drawback there lot of torq tweeks the monos and have to rearch them once a year. the last camaro i did we put a three leaf spring on it with a caltrac bar it work great it ran a low 10 second run on 12 inch tires. also what we learned dont use poly bushings there to hard for that set up made it to stiff went to rubber and everything could flex. any other questions let me know.
tony

Were building a Hemi Henry J. The car has a 67 camaro fr. Clip. I was planning to make room for wide tires by ( instead of a sub frame ) cutting the rear frame in fr. of the leaf spring, then narrow the section with the spring and put in back in the car like a sub frame but no four link. What do I lose ?

What do you all think of the new "fad" of using truck arm rear suspension setups like what they use in NASCAR on street rods & muscle cars?

I have read several articles about companies making conversion kits for them... Anyone on here have any experience with these things?

Ran a Nova many years ago with a big torque motor, I used the multi-leaf springs with Lakewood J-bolt slapper bars, worked great on the street and the track. Suspension set up at the track was a simple matter of installing the pinion snubber on the rear and travel limiters on the front to kill some of the lift and help the weight transfer.

It's been a little while since I have been involved in the drag strip end, but one of the set ups that worked real well on mono leaf cars like Novas and Camaros was ladder bars with a slider box to let the rear axle move forward and back on the springs. This took all the binding out. I've seen 9 second big block cars hook up solid with this set up. I would think this would work decent on the street also. It's a simple and clean look too.

Pat

Originally posted by AHSOM70
What do you all think of the new "fad" of using truck arm rear suspension setups like what they use in NASCAR on street rods & muscle cars?

I have read several articles about companies making conversion kits for them... Anyone on here have any experience with these things?

Hardly a new fad,but from what I have read this set up is supposed to give you a little from both worlds Street,and strip.Its not all street,and not all strip. I would like to hear some input on this set up also.I am talking about the set-up where the links mount up under closer to the center of the vehicle,not the one with the 1 foot or so links.

Doesn't the rear connecting point on a leaf push up on the frame,and the bending of the leafs?

i have made a full floating set up for my 50 chevy and used comp ladder bars and used a track rod with stock 50 chevy springs this work good and takes the of the whined up out of the spring and works good and the ride is not to bad. i had lift bars on it and the ride is better with the ladder bars on it with the floating setup. roads are not to good in bay city and it is as good as my 90 chevy two wheel drive truck. if you do a four link i wound use a panhard bar or watts linkage the track rod on this type of suspension is not as good as the panhard bar it will keep the rear end from moveing side to side in a hard turn the panhard anchors the rear end to the frame instead of holding the axle to the lower bars there is to much flexs with this setup on the for link or ladder bars on the street .it seams to work good on my 50 the springs help keep the rear end in places side to side but i had the trackrod with ladders bars on a tub gto and i all most drove the car off a bridge with this set up .