What do blade lenght, pitch, number of blades and rounded or cleaver blades do different from each other to give one an advantage over another?

Ohhh mannnn thats a long answer dude. But... ever y hull design likes different props. You are better off asking what to use in your brand of boat and what is most important to you ie.
top spd
midrange
holeshot
handling
For example , my baja likes a 3 blade mirage or laser for top speed but the bravo 1 4 blade is much better for everything else. [ thats why i have 2 props]

MY COMPANY MAKES PROPS OF OUR OWN DESIGN. WE COPY NO ONE. I HAVE A BOAT THAT I HAVE HAD THE EXACT SAME PROP DIAMETER AND HAVE CHANGED THE RAKE THE CUP FROM A MICHIGAN CUP GUAGE AND HAVE CHANGED THE CUP FROM AN L SHAPE TO AN ELEPTICAL AND EVERYCHANGE DOES SOMETHING. I KEEP THE SAME AMOUNT OF FUEL FOR EACH RUN AND THE ENGINE IS THE SAME. I HAVE HAD THE BOAT FOR TWO YEARS AND HAVE TAKEN TOP END FROM 72MPH IN 3/4 MILE TO 80.1 IN 3/4 OF A MILE GPS JUST WITH LITTLE ADJUSTMENTS ON THE PROPS.

NORMALLY THE CLEAVER IS FOR GO FAST TOP END AND DOG EARED FOR WEIGHT SLOWER BOATS. NUMBER OF BLADES CAN REDUCE DIAMETER.

BUT AS SAID DIFFIERENT PROPS DO DIFFERENT THINGS ON DIFFERENT HULL BOTTOMS.

FRANKIE

OK I have 3 blade 21p cleaver props on my 5000 lb. 28 cig w/ twin 300hp sbc's can are the props I have a good prop for top end? if not what would be a better prop?

Far from an expert, but I think cleavers provide no bow lift and are basically surface props. If you want to try a pair of 21P mirages when you are up at Lake Erie, let me know. I think the mirages will work way better than the cleavers.

On the 402 Forumla a set of over-hub cleavers (21") ran 53 mph (and got on plane slower than a freight train), a set of thru-hub cleavers (21") ran 57 (but at least would get on plane reasonably), Mirage (23") ran 61 and 4B Bravo-1's run 58-59. However, the 4B's are 7 mph faster at cruise than the cleavers and about 4 mph faster than the Mirage.

Your results may vary - Greg