From this thread that we hijacked:
https://forums.iboats.com/threads/2010-tahoe-q5i-4-3l-will-only-make-3500-3700-rpm-32-mph.767383/
"nola mike said:
I only got 42 mph/4400 rpm the other day with my new 4 blade/9 aboard. Haven't tried solo yet, but with old 21p and just me I'm getting 47/4900...