Variable hydraulic lifters for 440 engine

I have never thought I might need a variable duration lifter. Not even with the 292/292/108 installed in my 367. Not even with a 4-speed and 3.55 gears.
Your Ica is 68* to my 66*;
My current cam could easily be reset to match your Ica.
Your compression degrees plus power is 216 to my 219
Your effective overlap is 68* to my 60, but roller lifters are notorious for long clearance ramps, so this number is IMO somewhat misleading.In other words, as to advertised numbers,where it counts; our cams are practically identical.
As to .050s yours is 238/244 to my 230/238; of which only the intakes make a difference. In other words Your 440 and my 367 should idle as good as the same.
Mine idles down to 550/500 in gear and pulls itself around the parking lot ......... with just 5* of idle timing.
Why doesn't yours?
IDK, but lets find and fix the secondary air leak and see what happens. My secondaries are jammed shut because she's a 750DP carb, the secondary air valves are mechanically flipped open by the primaries. They cannot stick.