1967 American rear suspension

There are plenty of poly dealers out there.  Summitracing, jegs, etc....just do a search.

The Thanks for the input. I ended up ordering a kit from performanceamstyle.com they say that they are for 2.5 inch wide leafs. I will try to freeze them and cut them to the right width. At the same time I am building a set of home brew Caltrac bars. I came across a picture on Google and was wondering if anyone had some info on it. It looks like an adapter to eliminate the front trunnions and spring to convert to coil over spring.

There used to be an adapter for the upper trunnion to use a coil over. Post a link to the pic! It wouldn't be real hard to fab such a bracket. 

Okay. I looked up the pic on Google and got a better view. That is a complete billet piece on top that bolts to what appears to be the original upper arms. I'm pretty sure it was a custom one-off piece. I've never seen it before, but I haven't seen everything. The spacer and horizontal trunnion bolt have been removed and the piece holding the coil over inserted. That piece is also machined for a upper ball joint. I suspect a Mustang II spindle is used, but it could be a late model (71-83) small car spindle. You could weld something similar up from plate.

A better bet would be to just replace the spring, but keep the trunnion. To do that you need a circular plate that will fit the top of the trunnion with tow "tabs" to bolt a shock to. Need the same for the top of the trunnion. Insert in tower and hold in place while you drill a couple 1/4" holes through the tip pf the tower and into the plate. You could thread the plate, but I think I'd tack weld a couple bolts to the plate, making studs, then push up with the shock attached. Should be easier. Yes, 1/4" bolts. All they will do is keep the plate in position and the shock and plate from falling out when the car is jacked up, there will be no pressure on the bolts. Use at least grade 5 bolts though, as hardware store ungraded bolts are of random quality, graded bolts have to meet certain specs. Grade 8 won't hurt, but not necessary. Use grade 8 for the cross bolts holding the shock to the plates as they will have weight on them, and any bolts with shear forces. 

The plate on top of the trunnion needs to be held in place also. You can drill into the spring seat and use a couple bolts or weld tabs that extend over the sides. A 1" tall piece of pipe that has an ID the OD of the top of the trunnion would be nice. Then you could drill and tap into the sides of the pipe so the bolts catch under the trunnion when screwed in. You need something to keep that plate from skidding sideways, so I'd use grade 8 bolts for that if going through the top.

Instead of coil overs you might consider air springs. Don't have to have on-board air, just a hose and valve for each wheel. Set the way you want then check every month or two just like you (should) check your tires. TomJ runs his 63 American roadster that way. Relatively cheap, the on-board air and control systems are the expensive part of air ride.

See http://sensitiveresearch.com/1961-Rambler-Roadster/construction.html#frontsusp.  That's the older trunnion suspension, but it's close enough to the later trunnion that the same ideas work.


Edited by farna - Dec/05/2015 at 5:29pm