Install an open rear end in a 47-54 Chevy Pickup
There are a number of kits on the market to mount an open rear end on these trucks however some of these kits can be rather expensive. The entire suspension system (not counting shocks) used in this installation cost a total of $40 from a local wrecking yard. I added a set of traction bars purchased at a swap meet for $10 and the '78 Camaro 10 bolt posi unit was purchased for an additional $180. The rear end was rebuilt and a new set of 3.08 gears were added which brought the cost for the posi unit, including the purchase price, up to $650. Total cost for everything needed for this installation came to $700. Not bad really.
The springs and hangers used are from a late '80s model Dodge Caravan. Using the Caravan suspension makes this a pretty straight forward installation that will require a minimum of fabrication.
One note however, if you choose to use the stock Caravan springs as I have, you should use some form of traction bar to help keep spring wrap down on accelleration. These springs weren't designed for a rear drive vehicle and your "U" joints will live a lot longer if you use a traction device. You can have a set of springs made for a hundred bucks or so if you don't like using traction bars.
One more thing to consider. Caravan springs come in basically two varieties, 4 leaf and 5 leaf. Under normal circumstances I would use the 4 leaf springs but since this truck will see some towing I decided to use the 5 spring setup instead.
The Caravan springs fit into the stock Camaro spring sadles perfectly since they are the same width, and the sadles are designed to maintain the springs in parallel making this installation pretty easy.
Once the springs were mounted the whole assembly was fitted in place. The picture on the right shows the front spring mounting bracket and how it naturally aligns to the outside of the frame rail. The rear bracket convienently aligns under the rear rail. How much easier could it be?
Here you can see how the rear hangers fit under the rear frame rails. The hangers are a "Y" shape so a small bracket will be added to the inside and outside of the frame to add strength.
One of the small modifictions normally made on these pickups is to move the axle centerline 2" to the rear of the stock location. The rear wheels were not centered in the fender opening on these trucks because the stock suspension was designed to move the wheels rearward as weight was added and the springs were compressed. With modern parallel springs rearward movement will be kept to a minimum so the axle can be aligned so the wheels will be in the center of the fender opening.
Everything is aligned and in position. Now it's time to make some brackets.