From Wikipedia:

Following the withdrawal of Formula One, the event was assumed by CART for 1983 and 1984. The circuit was modified with turns 1, 6, and 10 connected in a continuous straight, producing a flat 1.125-mile distorted oval. The two races were contested over 178 laps, a distance of 200.250 miles For the 1984 running, the exit of the final corner was widened, increasing lap speeds by around 7 mph from the previous year.

So I guess there was a 1984 race. This is the only mention I found of that year at Caesars Palace.