[DeTomaso] exhaust gasket for Hall big bore

[Lee Farrell]

Does anyone have advice for the gasket at the header-to-exhaust pipe interface, from a Hall big bore to a stock exhaust pipe?   The SOBill data base says Fel-Pro 2014, with a 2 1/2 inch ID.   This looks fine for the stock exhaust section.   But the Hall output is a flare or bell shape, with only a lip for a flat surface, and barely reaches to 2 1/2 width by my rough measurement.   There would be very little, if any, gasket under the flared lip.
Or do you use a "donut" gasket, like Steve Wilkinson lists?
thanks
lee farrell