They are ground at Comp.

I also dug up my data today on my favorite "truck" cam. Comp LSR 215/223 .604/.607 112LSA. between 3000-3500 its up almost 50lb*ft. I actually should have spun the motor out a little more to find the peak RPM. It would have been soon after Im sure.

 

^^ That graph is from a larger engine, with LT's and heads, that isn't exactly a 5.3

Read this:
3+

 

Obviously, thats why i added the notes, but its easy to look at the results and extrapolate that its a good cam that doent give up low end.

Ialso did a cam swap on a stock 5.3l with headers, and it made 46fwhp with no loses as well, from 344hp to 400hp.

It was 1 step up, the 219/227 LSR cam.