What is his cruise speed at 3200-3500 RPM?

We boat the Missouri River, which is quite sandy/silty. Labbed props don't last here. I hate to loose top speed, but would like to gain cruise speed. The 380 likes to cruise 3200-3400 and mine will run 38-42mph in that range. I wonder what the 4-bladewould do for that. My dad had a pair of 25p Hydromotive QIV's, but i was told those are a stern lifting prop that is designed for stepped hulls.

I would have to ask him because I am not sure. I do have a set of stock used 26p 4 blade Bravo 1 props for back up and long boat trips, and notice about a 2 mph increase at the same rpm range as my 3 blades in the aprox 2800-4200 range. Top end I lost 2 mph and about 200-300 rpm. I heard that too about Hydromotive props being stern lifting. Bravo 1s might be a better choice with a mild lab/blueprint.

while we are on the topic of speed.. how fast will a 00 vyper with 454 mags go?

Not worth it to me at only a 2mph gain. I noticed you said 2800-4200. Does that mean the 4-blades will hold plane without tabs at 2800. The 3-blades really plow at 2800.

I had a 99 380. It would run 70 ish in completely flat water. Add some chop and 65 would be about it. Bottom was jacked, I would buy one without steps before I bought a 98, 99 or early 2000 twin step. Just my opinion.

I followed your advice, which is why I went with this 1997. Very happy with the performance, of course would love more, but remind myself of what I have!

Yes, the 4 blades will let you plane with and without tabs slower, and are better in real rough water.

I agree, if I get another Avenger I would like a 2001 and up. Mine likes a short distance about 1 foot wind shop in the same direction for best speed. Too rough, or smooth I lose speed.