Yes you are correct, the 26120 is probably a better choice for a big block. I used the 26120 springs on my Duster engine and they worked fine. I took a look at my notes and it appears that I also used the 26055 beehives on a 505 engine and I used the 26056 beehives on the 427 inch SB Mopar that I did a few years back. I've never had any lifter noise issues with any of the engines when I used beehive or conical springs. Every time I've ever run into a clattering hyd roller lifter was with a conventional dual spring with a damper. May or may not be related but that is my experience.