So besides the ram horn style will the block hugger style work
It will if the foot notes for that header model number states that they will work with your application.
1965-'70 had the steering gear box sitting behind the front axle the same as a Camaro. The header has to clear that. As such you can not use a Chevelle header as the 1968-'72 and all later cars had the steering gear box in front of the front axle out of the way (such as the change between a 1969 to 1970 year break). If you find a header to clear the steering gear box you also need one that accepts a Power Steering pump, and Air Conditioning brackets as well.
In the good old days you would go to your local speed shop and talk to the guy behind the counter. He had paper catalogs of every product he sold and could check those foot notes for you. Call a mail order business and you get some one on the phone who was raising money for charity the day before or sold slushies at the Kwiki mart. You could ask him to check the foot notes but I will wager his computer is going to say it fits and he will ad assuredly not to scratch the paint or ding the tubes if you want a refund if his computer is wrong.
Headers help race cars that don't run mufflers. On the street they are hype and marketing. As has been shown the dyno testing the 2½ inch Ram's horn cast iron manifold flows as much as headers below 4,600 RPM. They don't leak, or rust out and help keep under hood temps down as well.
What you see in car mags (back when they still existed) was put there by the advertisers, not the editorial staff looking out for your interests. The adds paid for the mag by your buying into the hype.
Do headers help on a race car when run open? yes they do above 4,600 RPM they make more power, But even above 4,600 RPM if you have mufflers and tail pipes the effect is halved. Not to mention you need free flowing heads, a solid cam and decent valve train to spin it that high.