Hey Juan Lopez. I have a built 301 on a Manco go kart. Not nearly the amount of aftermarket hop up parts available as the smaller engines, or even the 420. With mine I installed the billet rod and flywheel, 50 lb valve springs, twister 250
cam, ported stock head, milled .040", header pipe, and rejetted stock carburetor. #40 jet on the main and drilled the pilot jet to .021". Also removed the governor obviously and a low restriction air filter. Also put in a 4 degree advance key, as even the billet fly wheels on the larger engines don't have the built in advance like the smaller engines. Kart runs real strong.50 mph with just me in it, and 46-47 with 2 adults on board. 40 series torque converter. Only part that was inexpensive was the twister cam. Sold by OldMiniBikes Warehouse. Flywheel and rod are just as much as the ones for the 420. Before someone jumps in and starts giving me greaf for mentioning OldMiniBikes Warehouse, I'm just trying to help this guy out with his build and that is the only place I have ever seen that cam advertised. Half the price of most others. I have read all about the souered relationship between Hent and OldMiniBikes.