A question of HP, gears, and RPM

[Animal Magnatism]

Hi all,
Don't know if you remember my combo, but I've got a shallow V (Like a GN I guess) with a 565BBC and a 1071 blower running racing gas. Intercooled. 2x1150 dominators. BDS comp. manifold. Roller cam (284/293. .799/.765 @114). Pro-topline heads(360cc. ~410cfm@0.70). Blower is currently 10% under, Running 5lbs boost. The boat has run 95 at 5900 but was limited by the rev limiter. It should run 105 at around 6500. I guess its making around 1040hp at present. I'm currently running 33 gears and an 11.5 x 16 prop.
I want to up the blower to 20% over, which I think will give me around 16-17lbs. I want to maintain the 6500rpm limit and are going to change gears to suit.
My question is: If I'm getting around 1040hp now, what HP would I expect to see with 16lbs of boost, and, what gears should I go up to, to keep the RPMs at around the 6000-6500 mark.
Thanks.
Paul

[Schiada76]

AM
I've got a 19' Schiada semi v running a 500ci BBC, 871, 2-1150's, 13% over, 11-12#'s boost on AV gas. It was running close to 100mph @ 6800-7000 rpm with 12% gears.
I'm switching to 37's and going injected. JJ at Beaverfab said he knows guys pulling gears in the fifties with that kind of HP. The taller gears will keep the rpm's down.

[Animal Magnatism]

Thanks for the reply.
Anyone willing to take a stab at HP, given the above combo and 16lbs boost.
Paul

[superdave013]

I say you will be in the low 40% range. 40 ~ 45%.

[Schiada76]

SD what's your input on me using 37's as a bench mark when I'm all back together?

[superdave013]

never know until you try. I will say that those 12's had to go. JJ knows what up and is pointing you in the right direction.

[Schiada76]

Thanks.
I've had a hard time getting set up input on the 19'.

[obnoxious001]

I would think maybe even higher gears for the 565 with 17 lbs boost. Wild HP guess based on 2.25 HP per inch might be 1275 HP. I used 2.25 based on a smaller engine that made that type ratio at 17 lbs boost on dyno.
I used to run a 45 with my 505 cu in turbo engine, maxed about 15 lbs boost, 11 1/2 x 15, maybe 900-1000 HP, about 5800 rpm in a 20 ft Schiada. I would guess into the 50's. Some of the Aussie ski race boats were running about 70 %, with no transmission. Not the fastest off the line, but look out at the end of the first straight!

[Animal Magnatism]

So you think an increase of 10lbs will give me around an extra 250hp??
I have no idea, but am interested as this will obviously have a bearing on what gears I go for.
Also, what is a good 2 speed gearbox (eg. Lenco) to use.
Paul