Originally Posted by troop1943
I have a 1936 ford pickup with no suspension under it.
I would like to install an opendrive chevy rearend in it, using the original ford crossover spring.
I have no experience in doing this, so any help will be appreciated.
This is doable but needs some additional locating bars.
The old enclosed drive line supplied the structural strength to keep the rear axle located properly relative to the desired position under the frame and supported by the transverse spring.
The transverse spring holds the frame/body up over the rear axle and provides side to side support and location. But such a spring has no ability on it's own to locate the axle in the front to rear (longitudinal) direction. This situation is most similar to when coil springs are used on the rear with an open driveline.
Using Chevrolet Chevelle as an analogy, when they went to coil rear springs, they put in 4 point trailing arms to locate the axle. 2 trailing arms are exclusive to longitudinal (front/rear) location. The 2 inboard arms are angled inboard to provide lateral/transverse/side to side location and are mounted above the longer out board arms to provide roll control preventing the housing from rotating around the axle's centerline.
In your case I think pair, on each side, of outboard tailing arms parallel with the frame rails terminating to a fixture on the rear axle such that the arms form a parallelagram. These will work for longitudinal and roll position management. The transverse spring will furnish suspension and lateral support duties.