Dino 5686's motor in 4996? Help.

In doing some research, seems Dino Chassis number 4996 has the engine from Dino 5686. 4996 has been in California its whole life while 5686 was also in California most of its life. 5686, according to the registry, traded hands from JEM Motors, Symbolic Motors, Ed Brown and Bob Norsworthy. Trying to put the pieces together and find out when 5686's motor was removed and why.

Any help would be greatly appreciated.