Grievous isn't wearing cortosis armour. Don't know where you got this from. If his armour is made from a special metal that would be Durasteel and you can still cut that with a lightsaber although it's quite hard to do so.
And even IF he would have a cortosis armour. I have no doubt that Revan can do the same thing to him that Mace (crush his chestplate) and Obi-Wan (cutting his arms of; destroying his lightsabers) did to him.
So Revan will win this and he will do that with ease.
sigh..EU is not a pile of shit on the street, it is made for a purpose, this stuff did actually happen and it connects perfectly to the movies. So if Revan was powerful because EU says it, well then he is no way overated, and you are saying GG is the Roxxorz, because every one of your damn threads has GG against someone who could completly overpower him.