1.5 or 1.6 about same price. Does one get more power or a larger lift. It’s hydraulic roller lifters. Does anyone have an estimate on pushrod length with standard deck height and speedmaster heads?
Since you have nether A D your using speedmaster heads, where do the heads ports start to loose flow? I, myself like to lift the valve as much as possible or at least to where the maximum amount of flow happens in the head. This is not always possible but I try.
There isn’t a lot of power to grab unless the build is at a minimum, a pretty hot build or race build. But there is power there.
If the flow curve of the cylinder head tops out at .580, lifting it beyond that on a street car doesn’t really pay off. If your cam is a .500 lift, then adding another .030 helps a little.
Same again if it’s a .550 lift and you add .030 or .035 more.
Coupled with a longer duration, at the higher lifts, the engine starts to breath in pretty deeply.