When I bought my bow online it came with arrows, but I don't know if they are correct for my setup. I'm about to order some custom cut arrows online for the first time and my bow is setup is a 27.5" draw length and a 55# weight. What arrow spine and arrow length should i go with?
Assuming you're shooting a 27"or shorter arrow shaft and a 100 grain head, you should probably be looking at something with a .500 spine.
At 28" you're right on the edge of the .500/.400 range. IMO you'd be safter with the .400s as you're always better to err on the stiff side than the weak side.