Issues Continue. LOL. Header gasket blew, what brand to replace it?

[UATahoe]

I am running Dougs tri-ty headers that have an oval port design. The headers are for 73-87 trucks. The motor is a 383 with vortec heads. Any resommendations on what header gaskets to buy? I used the ones included wth the Dougs headers and it blew out this morning on the way to work. Sounds awful. LOL. The whole suqare round or oval port thing is messing with my head. Any suggestions on which style gasket to get (round or square)? Thanks guys!