I'm older but I'm with you on the look you are after. On this forum, it is mostly folks who argue over whether their cobra is a "real cobra" versus a replica. Good folks, they just have different values than me.
Like you, I am going more for the custom look with a cobra feel. I'm putting in a small block that I can maintain and drive regularly, I plan to customize the interior with a center panel, using 17" rims and low profile tires, and I'm going with a radical paint job.
I won't even have to entertain all those "serious" questions about whether it's real or not. I don't care. To me, it's a street rod that resembles a cobra and that's good enough for me. Build it the way you want and ignore the comments. You can follow along with my build at
http://www.pflanzer-aviation.com/RedVenomCobra