5.3 ls volvo penta "legend" pump performance suggestions/information with AB impeller

Hey,

Ive been testing a 5.3 ls style engine in a 19 foot scarab with a pjx volvo penta "legend" pump and a AB impeller. The boat does really well but i need more thrust. It is a stock 5.3 and claims to make 379 lb-ft at 4300 rpms and 344 hp at 5100 rpms. So i just put in a AB impeller upgraded from a C. Since i have more surface area on the impeller vanes should i not bore the nozzle to match? Ive been researching mixed flow pump optimization and cant find much material does anyone have any good books are good tech articles on mixed flow pump performance/theory?

Thank you all for your time this is all new to me and i have no idea where to start researching these topics.

I just wanna go fast

nathan