Had good luck with a comp cams K kit for my 69 Camaro.. granted it's an SBC application, but the kit comes with matched springs and everything else you need. I like the fact that tech support will make sure you're getting the right package for the application. also popped for a cam degree kit from them, and a degreed balancer from fluidampr, just to wring out as much power as possible, and to make timing it simple.
As for durability, I take long trips with it in the nice weather, and she'll turn 4 grand all day long on the freeway, with a lot more top end power to spare for passing.
Tom