Refering to people like me, who build thier own stuff, instead of paying others to do it for them. My point is if I was building a Sbc, sbf, bbc, etc etc I could go from spring maker to spring maker and find published specs of valve springs that will meet my needs. For example, all the past talk of using 32v 4.6 Ford springs in a 24v. While yes, seat pressure is comparable to "aftermarket cummins springs", they do not do well in other areas. Im pretty sure there was talk or rumors of a company selling these springs as "upgraded" springs for a 24v. So if that is/was true, anyone who bought those springs could have major issues with running them and a larger lift camshaft.