Conrail had 135 "fightin fifties" numbered 6700 through 6834 and built from 1983 through 1986. Conrail's fleet of SD50s (the second largest in the country) was delivered with a number of variations from "stock" EMD units.
Conrail's first three orders (delivered in 1983, 84 and 85) all came equipped with EMD's older Flexicoil truck instead ot the standard, at the time, HTC-II truck. This was because of Conrail's irroneously blaming the HTC truck for a number of derailments involving AMTRAK units. It turned out not to be the fault of the truck, and the last order that arrived in 1986 was delivered with the standard EMD trucks.
The second two orders (6779-6834) were also delivered with a large 4500gal fuel tank, as opposed to the 4000gal tank on the previous two orders.
For a more indepth analysis of the Conrail SD50, visit the CRCYC.