A500

Yes the A500 and 42RH is the same tranny. The 42RE is the elctronically controlled version that came latter. The 45RFE/545RFE is an all new tranny and only bolts to the 4.7/3.7.

The 89 Shelby Dakota was an oddball built by Shelby when there were no v8 option for the Dakota.

FWIW, there were A500's, A518's and A618's. The A618 is a beefed up 518 that came behind diesel engines. There was also a 44RE which was a beefier version of the 42RE.