Props?
 

I am trying to tweak out more speed out of my single carburated HP 500. When I bought the boat it came with a 30" Bravo 1 prop. I exchanged it for a 28" Bravo 1. I think it has better low end performance... Top end has not changed. Also the maximum RPMs I'm getting out of it is only 4800.

Someone also told me that an MSD box would add more HP. Would one help an HP 500?

i have heard through the board that many have not measured a performance gain by changing to msd or similar. I think your best bet for the buck would be to lab finish the 28. John at York has received many endorsements on the board. $150 or so and expect about 100-200 rpm gain. that would put you at the peak horsepower for the 500hp ( ~5000rpm)

An MSD box isn't gonna help you on the top end unless there is something wrong with your current ignition. Get your prop labbed or maybe even go to a 26" prop. You need to spin that engine faster to make power. You should turn 5200rpms.

29Warlock

You may want to try a 26-27 Hydro, I am running a 500efi w/26hydro and hit 5250rpm at wot, Your boat weights more I think but it may be woth a try. Hydros are a little faster top end, but slow in the hole.:cool:

WILL

You really need to spin an hp 500 at 5400 rpm, they like the rpm and you need to have someone repitch your 28 to a 27 lab finish and youll be right in the ball park