Duster 360 727 tti dougs sanderson

Hi there
Sorry for beginning for several topics around this case, but i didn't found correct answer.

My car 10/73 so "74 Plymouth Duster "gold duster" original K-member 318.
Now it got 360 LA engine and Edelbrock Performer RPM cylinder heads. measured from dyno 400hp/550nm, stock engine bay, with polyurethan arp mounting kit.
727 transmission with deep aluminium oilpan.
Column shift "quite original"
Mini starter also
Power Steering box "quite original"
Deep oilpan Milodon 30940, yes have to cut the K member, i've done it.

So what is right headers for me?
Sanderson DD8
TTI ?
dougs 453

I.m losing my mind with these, also don't exactly know where is good offer?
Please help me with this.
Thank for everybody, keep health...