Carl, the 1960 C10 is getting a Lugnutz prepped T5, it has a 3.90 rear gear which will remain. I have a few other things in mind for the engine, it's getting a Melling CCS-1 cam and lifters. I have an "848" head that is being machined. I have no allusions at getting 300 Hp from this engine, just a strong running engine with ample torque.
As for which manifold , well that will require more research. I understand that the carb choice will make or break this build.