Boost pressure on the gauge really does not change based on rpm. Boost pressure changes based on the load placed on the engine. If you rev an SC'd engine in neutral to 5000 rpm, it will hardly show any boost. If you put a heavy load on it, it will make boost pressure. If you are at WOT, the engine should make the about same boost pressure whether its at 4600 or 5100rpms. Boost pressure is not the amount the air/fuel being moved though. At more rpm, the blower is spinning faster and moving more air/fuel mix.

The 575SCI makes 4# of boost stock. Recommended WOT range is 4800-5200rpms. Run it at 5100-5300 to make the most HP and get the best top speed. Running it at 4600rpms WOT is harder on it than running it at 5300rpms WOT.

I would not go with 5 blade props. You don't need them and they are harder on drives. I highly doubt you would be able spin 27 Hydros to even 4800rpms.
I would get a set of Bravo 1 28's and have them custom labbed by BBlades. They will be a good all around prop with a very good top end #.
The 29 Mirages are too big. You may want to try some 27's. That should get the rpms to around 5000 and probably a mph or 2 faster than the 29's.

Griff, i did not say anything about 5 blade props...but 4 blade hydros are thinner and lighter then the merc and he ran 28 4 blade mercs, so why would a 4 blade 27 hydro not work ??

The Bullet was a rocket..In cool air it would bang the limiters everytime I pushed it. It needed more prop but..Running Erie i liked the Mid range

I built the motors In the TG for blowers..Low comp, big blower cams. But never put them on. I just havent had the time to fool with it. It runs about 75 and only running it once or twice a year...Thats fine... Unless I find a Screaming deal on a pair of 10-71s or 871s

I still say send a pair of 28s to Brett and tell him what you want it to do...He has done props for many of Bullets...

Well guys I ended up trying the 27p 5 blades by hydramotive and they were awsome. Gets on plane sweet good mid range and the best of all I seen 80 mph at 5200 rpm. These props are awsome. I was able to trim the boat up the furthest with these props. The 5 blade props have so much more control over the boat than the 3 or 4 blades it is awsome !! Now I'm just stuck on weather I should do the boost and ign. Upgrade by AZ SPEED ? It sounds like a really sweet setup they have. Taking the blowers to 6 bls of boost, msd ignition, upgrade the computers, rev limiter from 5300 to 5600. I really don't want to mess with my reliability. What should I do ?

I feel stupid !..Somehow i thought you had 3 blade 27s.. not 5 blade...I would have loved to try those on my Bullet !
Be careful though...I bet they will destroy Bravos If you are not careful

The only way i would jump to 6lbs of boost is with an Intercooler

Well after getting a set of 27 5 blade from hydramotive and a set of 28 4 blade bravos from bblades. I ordered a set of 4 blade hydramotive 28's of offshore only. They turned out being the best and at a 1/4 of the price !!! 81 mph @ 5200 I love it. A few more dollars come on 85 !!!

Congrats on 80+ MPH !!!

Just .02 here ..... Do some background on AS ....no personal experience here ....just what I have read ....check it out ....looks like your definitely headed in the right direction ...good luck ....m