I prefer four blade or five blade to reduce slip. but hey ...try em all if you can

I'm running labbed a Bravo 1 4 blade on my 28. I might try a Mirage plus now that I've lowered the drive, but getting on plane in any reasonable amount of time could be tricky.

X dimensions,,, is this my prob ???
 

Ive added about 60 hp to my already 490 hp 502. I think Ive have picked up maybe 2 mph , its a lot quicker getting there but the top speed isnt increasing like i hoped. I measured the distance from the bottom of the boat to the prop shaft , it appears to be about 7.5 inches. This is on a 21 foot baja. Should i be thinking about a shorty or the cut down bravo Maxx is testing. Best MPH to date , 74 at 5500rpm. thx guys...sj