I went with 16/32 gears. 428 chain. It took 111-112 links I think. Stock swingarm. At 60mph the speedo shows 50. I still haven’t got a corrector thing but will eventually.
I’d check the 250/300 swap Facebook page. There’s a sticky for parts list. All my stuff is from wicked grom except Ecu. I got that from hard racing. You’ll need a cheapo shift lever. I have a couple more videos to post to finish this series. Bike is complete and runs like a scalded dog.