A typical Gearing Class Destroyer was 3200 tons. It was the last class to have steam turbine propulsion
2 × steam turbines providing 70,000 shp (52 MW); 2 shafts
4 x 1,275 psi (8,790 kPa) boilers
The later classes had gas turbine propulsion, for example the Spruance Class:
4 × General Electric LM2500 gas turbines, 2 shafts, 80,000 shp (60 MW)
Both ships were capable of 33 knots.
So, a ship of this size needs a total propulsive power of 140,000 - 160,000 shp
Since the US did not build diesel engines of this power output, I'm not certain doing so is practical
from a weight standpoint.
The world's largest diesel engine. The 109,000-horsepower Wärtsilä-Sulzer RTA96-C, which first set sail in the Emma Mærsk in 2006, weighs in at a rotund 2,300 tons, and it's 44-feet tall and 90-feet long. In other words, the TRA96 is the height of a four-story building, and longer than a Christmas Eve line at Sam's Club. Within that massive exterior rests 14 cylinders that each consume 6.5-ounces of diesel fuel every cycle. And, if you like torque, there's enough twist to rip an M1 tank to shreds, though the massive mill churns at only 102 rpm.
So, yes you can build very large diesel engines, but generally they run at 100 or so rpm, and are massive.
Needed is a lighter power plant. First the US/UK used steam turbines. Then gas turbines. Steam turbines
work very well. They come directly from the electric power generation industry, and Iran makes them. The
boilers also come from electricity generation industry, and Iran makes them too.
So, it makes the most sense for Iran to power ships of this class with steam turbines, unless Iran can develop
gas turbines of this power range.