Hot Rod John is right. The question is not WHETHER to use headers but what the header options are. Speedway Motors has block hugger stainless steel headers. I don't know if those will fit a '65 truck or not but I would like to know because my son has one of those trucks and "stainless is forever".
As for leaks, I have a 350 SBC powered '32 Ford roadster with headers that have been on for 7 years with no leaks. I attribute that to quality headers with unwarped flanges, quality gaskets and stainless steel socket head bolts and stainless steel lockwashers tightened frequently after the first few runs as the gasket compressed.
As for noise, there is enough wind noise that the engine cannot even be heard at cruising or highway speed unless I mash down on the accelerator. Big Magnaflow stainless steel mufflers and an H-pipe in the home made exhaust system probably contribute to the quiet exhaust sound.
