[70c10-08]

Well I'm no expert on the RTS's but according to Wikipedia they say initially they had either your choice of either a 6V-71 or a 8V-71 Detroit mated to either an Allison V730 or a ZF HP-500 the later versions could've been had with a 6V-92 or an 8V-92 and the RTS's shown above with round headlights were prototypes built in 1970 the RTS 2 didn't begin production until 1977 I believe