Speedmaster Small block porting tips and results Part 1

Ive been looking at these for my bare castings, anybody have any experience?

https://www.ebay.com/itm/SBC-2-080-...s-Small-Block-Chevy-01-3008-100-/133148685069

SBC 1.6" Dia 5.010" Nitro Black Perf Exh Valves Small Block Chevy 01-3001+100 | eBay