Carbide Burr bits good source?

ok I got 4 Blackhawk brand ones from Fastenal. IDK if this is their "house brand" or if this is an extension of the old Proto/Stanley line of hand tools.

After asking on here I wound up ordering some from a company called "Benchmark Abrasives" I had bought flapper wheels and Roloc cookies from this place in the past/ they had sent me an Email for a "fathers day sale" on burr bits which I blew off at the time, not thinking yet of this project.... I looked on there like 2 days after their sale ended, it was either 10 or 15% off..... I ordered 4 from them, the extended length ones they had....
Ive got a bunch around here (never had the 6" ones before though) if I could only find anything in the abyss called my garage. probably have duplicates of the same style bits I got from Fastenal at least.....
all that I have are the "double cut" style/
got the bug to try and improve the ports on a slant 6 head if I can do so without ruination.