I did a lot of dyno testing with the 270 heads when they first came out. Made close to 800 hp with a pump gas 470 using the TF270 heads. I tested a lot of different rocker arms. They all worked just fine but the T&D were by far the best setup in terms of quality, fit and function. Here is an article where I used a fairly aggressive cam lobe with the Comp dual conical valve springs and a set of 1.65 ratio T&D rockers. I think the engine was making around 750 hp in this configuration. https://www.motortrend.com/articles/dyno-tested-dual-conical-valve-springs/