zz430 on airboat

hello all, new to site but had questions about maybe gettin more power out of my zz430 replica motor. any advice that might help would be nice.  

this is a trick question(mine not yours) what kinda rpm does it pull now.  

wot is 5250 dont want to spin prop much faster. the motor is very reliable so i dont want to go extreme, just wondering if you guys might know a few secrets about the zz430. im not a mechanic so please be pacient with me  

ok I had a feeling that might be your answer is that a 2 to 1 reduction. I don't know if you want more speed or what. if you pulling that kinda rpm you may want to look into more pitch on your prop.remember the tips should not exceed the speed of sound.at max rpm. is a variable pitch available. im sure they are quite expensive.and since I don't know what your after hull mods may be considered.A flat bottom creates a huge amount of drag. so really that engine is doing its job. Tuff where you at,get in here.  

you can TRICK the bottom into thinking its a tunnel hull with a rib down the center and outboard skegs for some stability.  

+1 question for tuff  

I went to A and P school.also grew up in Miami and spent time in the everglades on air boats. that drag on the Hull is part of what keeps them in the water.ever seen a flying boat. not a plane that lands in the water but a boat that skims across the water only a few feet above it.  

Geez,,,
So now we're flying at the speed of sound,,,
So let's see what the engine is all about,,,

ZZ-430 ENGINE SPECIFICATIONS

The base foundation of the ZZ430 is the ZZ4 Short Block (See ZZ4 Spec's for more information.)
Displacement: 350 cubic inches
Bore x Stroke: 4.00 inch x 3.48 inch
HORSEPOWER 430@5800RPM
TORQUE 430@4000RPM
MAX RPM 6100RPM
INTAKE #12366573 VORTEC DUAL PLANE
DISTRIBUTOR GM HEI
Compression: 9.6:1
Block: Cast iron, four-bolt intermediate mains
Cylinder Head: Cast Aluminum Fast Burn #12464298, 23 degree valve angle, Valve Diameter (Intake/Exhaust): 2.00” / 1.55”, Chamber Volume: 62 cc
Crankshaft: 1053 Forged steel, 1 piece rear seal
Connecting Rods: Forged, powdered metal, 3/8” bolts
Pistons: Cast Aluminum
Camshaft: H.O.T. CAM #24502586, Hydraulic Roller Tappet
Lift: .525” intake, .525” exhaust
Duration: 218 degree intake, 228 degree exhaust @ .050” tappet lift with a 1.6 rocker
Centerline: 109 degree ATDC (After Top Dead Center) intake, 115 degree BTDC exhaust
Rocker Arms: GM 1.6:1 self aligning roller rockers (Roller Tip)
Timing Chain: 8 mm single roller design
Oil Pan: 4-quart
Oil Pressure (Normal): 40 psi @ 2000 RPM
Oil Filter: AC Delco part # PF25, Premium AC Delco part # UPF25
Fuel: Premium unleaded - 92 (R+M/2)
Maximum Engine Speed: 5800 RPM
Spark Plugs: AC Delco part # MR43LTS
Spark Plug Gap: .045 With HEI Distributor (Less gap (.032) with points distributor.)
Spark Timing: 32* degrees maximum @ 4000 RPM
Firing Order: 1-8-4-3-6-5-7-2

The key to this engine is the heads,,, which flow very well as cast...
The valves are the severe duty ones from the Corvette LT-4 engine...
The heads are about $1100, which is pretty competive with other good flowing aluminum heads...
You have to use intake manifolds with the "vortec" late model design,,, which are available from Edelbrock or GM...
The heads are drilled for early 4 bolt or late center bolt valve covers...
You are at 5252 RPM's now and from that point on, Torque falls off rapidly as your Horse Power keeps climbing to max out at 5800 R's...
I believe you will be unable to get much more out of that ZZ package.
Your prop should be OK at 2600 R's,,, thru your 2.3 to 1 reduction box, it's 2282 R's,,,
I would not push my luck beyond safe limits that you are pushing now.
Do this,,, establish surface feet per second that the outside tip of your prop travels,,,
so let's take your 80" prop (hypothetical) at (size/diameter) 6.66' x (pi) 3.1416 x (RPM's) 2282 = 47746.413 feet per minute or 9.04 miles in one minute or 542.4 miles in one hour,,, speed of sound is bout 770 MPH, so our prop speed is not critical yet.
Do you really want to spin your prop much faster,,,
let us know
 
When the Flag Drops... the Bull Chit Stops...

sorry it took so long to reply,computer screwed up. ok my reduction unit is a 2.3:1 dont know how much of a differance that makes. Is there a different set of heads or a new cam that would get upwards of 500hp or am i going to have to get serious into this motor to get that kind of numbers.  

about the rib running down the center. when on dry ground you wouldnt be able to steer. For the boat that only rides the river, maybe an option, just not for me. I ride way to much dry ground.  

I don't think that your 350 Small Block will give up much more power,,, normally aspirated...
BUT,,, let's try a little boost, bout 5 pounds, 6 or 7 max because then heat gobbles up any gains.
Boost works like this,,, the air you breathe at sealevel is at 14.7 pounds of pressure or one atmosphere.
IF,,, you could boost to 14.7 pounds above the original 14.7 lbs... your displacement would double and your lil mouse turns into a 700 cube monster.
Again, you can't go that high for practical reasons, so let's get back to bout 6+ pounds, and you have a 500 cubic inch engine.
Now it's time to explore a bigger prop, more pitch and of course fuel enrichment to satisfy the needs of your large displacement engine.
Boost can be a wonderful thing because the power comes in progressive increments,,, nothing harsh or abrupt as nitrous.
Consider your options,,,
How big is your prop, by the way, since I pegged it at 48 inch
on the reduction box ratio, you can do your own math and good luck Pilot
 
When the Flag Drops... the Bull Chit Stops...

I corrected the figures for the 2.3 reduction gear and a steeper gear box may be something to consider or more prop.
 
When the Flag Drops... the Bull Chit Stops...

As far as boost, thats a bit more money than i want to spend. As reliability goes,what are we talking between rebuilds,and would the fact of possible water maybe hurt anything. I dont really know how a turbo or supercharger works other than compressin air.  My prop is 80 inch. if i put more pitch in the prop i loose rpm's fast. It pushes good on the ground i would just like to be to do the same ground runnin without puttin it to the floor.  

I believe our question,or at least mine is why.why more power.that engine is doin it if your prop tip speed is in theory traveling at 325 mph you can stand a longer prop.that makes tip speed increase and of course if pitch remains the same gives you more (in this case)push.an increase in pitch will affect push also.like the gear in a car rear differential at a given engine speed 5000 rpm you can keep changing gears and go faster until the engine can't push the car any more at that given rpm then you need more power.that is why reducing drag increases speed with out changing anything else.so why more power if you can't increase speed.yes you can add power to your engine at the expense of durability as you are at the safe limits of your engine now.  

gear box equals $$ and alot of it. I have a belt drive reduction unit so i cant just have the gears changed like a gearbox boat can.Same with the prop, just hate to spend almost 3 grand just to see what i might get out of it.