Mechanical Diode Converters?

Just had a local guy rebuild my 727 to go behind my 99% street driven 440 With 520hp and 535 ftlbs as per the dyno.

He wants to sell me a converter he has. 245mm with billet back cover, furnace brazed with mechanical diode, low stall stator.

To be honest whats required in a performance converter is getting me a bit lost. I have read up on the mechanical diode as that was new to me. Sonnax does not recommend them for street use however.

Prior to this I did email SMR Transmission and as per my cam he recommended a 3000rpm stall but nothing near as exotic.