Understand that Alum tends to flatten out under power while a SS is both stronger and holds its intended shape better.

Your V-8 has about 50% more torque at 3,000 rpm than a inline 4.

Stainless blades are often thinner, thus reducing the rotational drag as well.

Watch those rpms if you engine does not have the two knock sensors.

...two knock sensors?

Michigan Wheel Apollo 14-5/8 x 16 P/N 993203 is what I've got in mind.

As an aside, Cobalt used to use Mich. props on their boats. When I asked the Cobalt tech rep at that time, he said they work better for their boats. This was more than awhile back. I have no insight into what Merc did or did not do to cause them to change. Never asked.

New Mercs have two knock sensors, and they upped/changed the rpms upper limit when they did that several years back. I posted that and something like the engine serial numbers at the time, I do not clearly remember that specific detail now.

4500 rpms mine is a 04' and its upper limit is 5000
If I'm not mistaking rev limter @ 5200
Do you have any documentation to verify what spec is ?

I do not understand, I posted it.

I do know that a 2003 or so Merc 5.0 has a range of 4400-4800 rpms once warmed up according to Merc's info if that is what you want to know.

That is for carb'd engines, I believe.

Same for Efi in 2001, but MPI 5.0s were 200 rpms higher at each end of the range, or 4,600 - 5,000 rpms.

Mine's an '02 carb'ed 5.0L and 4400 to 4800 is the recommended range.

I got a 20p Piranha composite 4 blade. A big reason was I was boating on a lake/river with lots of stumps and shifting sand bars at the time. Nice hole shot and really didn't seem to lose any top speed (maybe a clue it had more rake than a sternlifting prop would have?) but I had 2 incidents of shearing a blade right off while slaloming. Once during the run and the 2nd time on the start. They replaced the blade free the first time, I didn't bother asking the 2nd as I had spares and its been relegated to back-up duty. In their defense their website specs top out at 250hp and I have 260hp, but they did say I should've been fine. I'm back to the 21p 3 blade alum Black Max now.

deepv...very interested in your Aplhpa 4 results.

Opinion on Solas -- they are a medium quality company -- props are not very tailored and performance is only medium --(that is exemplified by Seabuddy saying they have the same listing for OB and IO -- they are generic props --- there are better out there -- but they also cost more -

Opinion on tabs -- get good hybraulic trim tabs --- not a new prop

Opinion on going to four bladed prop -- great theory for solving your problem -- larger blade area -- better bite -- etc -- I had found in the past that all that was true -- but I could not relate the diameter and pitch going form three blade to four blade very accurately -- my suggestion there -- spend the extra money for someone you can trade the prop with -- four bladed props perform more differently manufactrurer to manufacturer than three bladed props --