Tri-y or cast iron headers??...and other exhaust questions

[Kootenay69]

I'm planning the install of my 302 in my 69FB:

Stock 302 heads, ported
Tri-Y or Cast headers
Stainless X-pipe 2 1/4"
Flowtech Warlock mufflers(with 3" cutout)
Stainless tail pipe with turndowns

I want the engine to breathe better through some headers at the same time keeping some sembelance of original equipment. So, Tri-y or cast headers??Who are the best suppliers for these?