I use ryzen 5 3600
and yes stock cooler
so you mean this case should be good right!
"can I overclock this CPU with stock cooler
Yes to the case & yes (a little) to OC'ing the 3600 on the stock cooler. However, the 3600 is a great CPU to begin with and little need to OC other than to squeeze out the last few bit o' power. With a little luck in the silicon lottery, some users have been able to squeeze an extra 11% in performance over stock. If you do OC, take it slow and keep an eye on your temps. If you plan to keep an OC and run intensive applications, then I would caution you to think of a better cooler. While the stock cooler is good, you'll want something a little more beefier. Here's a
video.
You'll want the fastest RAM you can afford as Ryzens love fast RAM , especially the 3k series so look at a minimum of DDR4-3200. Faster if you can afford it as the Tomahawk Max supports a staggering max DDR4-4133(OC) with A-XMP OC Mode enabled in the Bios. Keep in mind this is only with the 3k series CPU's. If you drop down to a 2k series, then the mac support OC drops down to a max DDR4-3466(OC)