What Header Gasket?

[Cadillac Kid]

Hello everyone.

When I bought my truck It had a pair of smog legal headman headers on it.
It has come time to put the headers back on the 350. I am a little confused on what header gaskets to get. Ive been looking on jegs and summit and seeing header gaskets with square ports, round ports, and all different dimensions.
The engine has square ports, but my headers have round ports. I am not sure what gaskets to get. Round port or square port? Here are some pictures of the exhaust ports and the headers. When I pulled the headers off, they had the cheap cardboard type gaskets on them (I don't like these).
What gasket are the proper type? Its a 1974 350 4bbl, for what its worth.

Thank you!

-Gavin