Small un seen little things...:)
 

My dad wont let me re do the 4.3 so Im looking for a few more mph, anyone know any small un noticeable (looks wise) things like a new flame arrestor (will that help?) just for a few mph more....

4.3l 262
carbed

From my experiences with boats, "small-unnoticable" changes net small-unnoticable results. In performance boating, there is no free lunch. If you want to see some gains in speed, it`s gonna cost you, especially with a 4.3. To be satisfied, you probably should sell your boat and step up to a V8.

Just my opinion.........

Yup.

one problem, its my parents boat. Whats the new 5.0 vortec's selling for?

Dear Hyperbaja,
Been there, done that, but it was a long time ago!

Install a straight tube instead of the bellows in the exhaust system in the outer transom plate. Little noisier but less backpressure (talk to a merc mechanic he will know what I'm talking about).

Advance the ignition timing two degrees past stock (buy a timing light, learn how to use it, and time the engine to the stock specs in the book plus 2 additional degrees advance).

Install extended tip spark plugs with a larger plug gap (get a plug catalog and study it to understand the differences between standard and extended tip plugs).

Rejet the carb for the type of altitude and weather you generally use the boat (buy a book on carburetors and study it).

Buy a book on props and understand the relationship between engine rpm and pitch and then send the prop out to a prop shop and have it reworked.

Once you make the effort to make these mods you will have learned more than the average boater and will have a better running boat.
Sorry it isn't any easier than that but learning about this stuff is the key to going fast!

Sincerely
Dennis Moore
FAMILY AND PERFORMANCE BOATING MAGAZINE

Noticeable performance gain from engine power alone requires significant changes. Those appear to be "out" in your case.

On a 20-ish footer, any change towards rearward weight bias will increase speed. I am assuming that your current topspeed is attained using positive trim (trimming past "neutral"). This shows that your hull/weight bias responds favorably to lifting the bow.

Moving any heavy item from the front to the rear will make it easier to lift the bow. Moving anchors to the stern, moving batteries back a few more inches, storing your cooler under a rear jumpseat, etc.. These will all give you either More bow lift at a given trim angle OR the same bow lift at a LESSER trim angle - both will net a speed increase.

Using a prop with bow lift (3-blade Mirage Plus) over a prop with minimal bow lift (Hydromotive) may be your best bet. On the other hand, it is possible that your boat will like stern lift instead (although I would be surprised).

A clean hull is a must.
Keeping the boat light is helpful (don't store a whole weekend worth of stuff if you're looking for speed).

Beyond that, it starts to cost money and becomes visible to the parents....

good luck

(nitrous can be hidden easily)

Nitrous.... :D
Clean hull--bottom paint with primer which parents wont let me take off....

Prop-3 blade 14x19 turbo stainless.
i gotta try some new props next year...

I did a "back to back" with a 21" Turbo and a 21" LaserII and found the Laser had significantly more bow lift. This was on a 22' Crownline with a 5.7Alpha

I ran a Turbo 2+2 4 blade on a 20 ft Mariah with a 5.7 260hp. and was not impressed with it's performance.
Since then I've been told that Turbo makes a great bass boat prop but a marginal I/O prop.
Call the MFG. of your boat with all of your numbers and tell them what you are wanting to accomplish. They should be able to help.
I have a friend that did that through his dealer and they came back with the VENGENCE three blade.
Smaller diameter and more pitch than his original prop.
Normally the only way he could get the speedo even close to the top of the speedo was empty on fuel and by himself.
With the VENGENCE 3 bl. he was able to PEG the speedo (not just get close to the numbers) past the numbers with 1/2 tank of gas with 1 other person with him.
In a nut shell--------GET ANOTHER PROP will be the biggest change you will be able to make, and maybe not get busted by Dad. If you play your cards right he might even go along with you, once he sees the difference.
Be verrrrry careful on asking for good top end and expecting a good holeshot for skiing. It's not going to happen!!!!!!!
On the other hand you could own 2 props. One for you and one for the "Family"
GOOD LUCK

Hey kid,
You better do something with my $10..or should I say yours now:D
Opies right the right prop is probably the cheapest speed your going to find.
I had great luck with Ballistic. They're stainless and come from the factory with a thinner blade , almost like being labbed but 1/3 the cost. New your talking about $300.
Still believe in Santa?:D :D :D Christmas is coming. This Santa has to get his kid a set of 12.50x33 Michelins:rolleyes: