This is a Snap-on rear spring spreader made years ago for Model A and B Fords. I bought this from Ed Johnson's good friend, the late Kenny Massie. It is shown mocked up with only a main leaf in the pic above.
The spreader has chisel type ends which engage the spring eyes, and a very stout acme type thread ratchet in the middle. The center dogleg is designed to clear the rear axle banjo. I've used it a few times and it works great! I've never seen a more robust tool for this job.
My goal is to make it through life with my eyes, teeth and forehead intact and without getting hurt. I believe this is one of the safest tools to be found to do this dangerous job.
Personally, I feel the KR Wilson spring spreader (compressor) is a very scary design to use, and would not try it. In the past I've used chains, jacks, and big forged steel C clamps. They work, but never again!