Yes, it is going to ride rough with the springs you have. If you remove spring leaves, keep the 2 top ( longest ) and remove every other one below them. DO NOT use any leaf that is badly worn or looks like it may be cracked. Do a complete tear down, clean up, and inspection. Add teflon buttons or liner between each leaf.
Be aware, your load capacity will be greatly reduced. Shock type is going to be something you have to work out once you get farther along. A simple crossmember across the frame rails and modern shock mounts under the leaf spring pads is easy enough to do. Mount the shocks with 2/3 of the travel for compression and 1/3 of the travel for extension. Look here for shock sizes,
http://www.monroe.com/downloads/install-instructions-guides/MonroeMountingLengthSpecifications.pdf Try not to get some odd ball shock like I did, I managed to pick a Ford Pinto rear shock to use on the front of mine.
I ran mine for years this way with decent results, but I was always worried about the fronts being old and only having four leafs, so I bit the bullet and ordered four new custom built springs from Detroit Spring Co. It was expensive, but worth it in the end for piece of mind and the ride. I am now back to 7 per side front, 8 per side rear at a much lower spring rate.
