Best exhaust manifold? 65 c10

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65 c10 short step
3 on tree..3.73 rear
235/55/20 100 spoke knock offs..bout 30" tall
86 c10 front end
80s vette? squareport 350.. 5 way, port n polish, 194 heads thumper cam
Estimated 375-400hp at motor

Current random long tube headers work fine sound fine they dip below my frame rail

(they do keep my starter Hot off highway amongst other short comings)
I'm wanting shorts like block huggers or 2 1/2" ram horns
Cast iron retains heat more than metal of headers
Which is better and either dump straight down or back at an angle?

Going 2 1/2 back to cut outs between bed and cab then 2 1/2" in 3" out xtube or 3" slightly after
Probably boring frame to lay up in it
Curve above axle and dump on the down sweep

Headers cool faster
Without work are ram horns better
What about c4 manifolds?
They seem to be headers already

Had anot her profile but can't sign into it

Thanx