Ron,
That 55 transmission is from a car. The main difference is the clock positions and the shift arms on the side cover. You would need the truck side cover to use that trans. As stated, longer bolts with nuts are commonly used to mount a car trans to a truck bellhousing.
The linkage rods on your truck are correct, just cobbled up to be able to use the Saganaw. It's possible to use the Saganaw in your truck, and many on this site have done it. It is a better more modern trans. It may only need some adjustment and tweeking for it to work well.
Fred
