The doughnut TooMany2Count is showing is the doughnut that would go on the front header because it doesn't have a beveled outlet. The doughnut slips right into the header opening and the bottom rounded part will fit nicely into a flared exhaust header pipe. The flange pulls up on the flare and will hold it together. The beveled header opening has a doughnut that looks the same except the rounded off part, like the bottom of the doughnut TooMany2Count shows, is the same on the top. A flared header exhaust pipe is also used with a flange to pull it up.
