To Anyone who knows much about 4.3
 

Looking for more power, now has underwater exhaust.
I would like another 100 hp if possible out of it.

im thinking:
Corsa exhaust (480 silenced)
Headers
Cam
Heads
Intake manifold
Carb (holley)

I know i will need a new prop and the back seat will rule out a blower (for now....:D )

Do any of those mods bring me close to 290 hp (190 stock) and where can i get them and a new prop for around 3,000 total?

Thanks
Tommy

100 HP for $3000. No problem.

Any style 5.7 small block will give you what you want, check on E-bay.

I would not waste the time on a 4.3-but a Procharger will do exactly what you want-no other mods.

see i told ya bro.. easiest way..

supercharge....supercharge....supercharge....super charge....
supercharge....supercharge....supercharge....super charge....
supercharge....supercharge....supercharge....super charge....
supercharge....supercharge....supercharge....super charge....
supercharge....supercharge....supercharge....super charge....
supercharge....supercharge....supercharge....super charge....
supercharge....supercharge....supercharge....super charge....
supercharge....supercharge....supercharge....super charge....

:D :D :D

Re: To Anyone who knows much about 4.3
 

Thru-hull exhaust is the best place to start my motor guy build's 300+ hp 4.3L with roller cam's and 9.5 to 1 compresion. 4.3L, it is based on the 350ci and all the same tricks will yeild an improvement. But if there is space a good mouse like the one travis has would be great. Even with a pro-charger you still need the exhaust to exit out the transom NOT the prop. The extra back presure makes the motor run hot. my .02 Charlie

Supercharger wont fit under the hatch and i dont want to cut through because i would need to cut the padding re do the ends....etc....

350 dosent add enough to be worth the cost i know someone who has one in the same boat, he has 3 mph over me. but his handles like a bus, takes longer to get on plane, has to cruse faster, just dosent feel right.

A Procharger looks like an AC compressor. It mounts on a bracket in the front, not on top of the motor.

If your buddy has a 205 or 230 HP V8 then he doesn't have much more than your 190 HP. But a 300 HP small block is fairly mild and would walk all over the V6.

He has a 260hp.

I would be happy to try a supercharged 350 (if it will be so much better...) because the motor mounts and flywheel are the same for both engines.

Anyone know of a 350 for sale somewhere???

And can someone give dimensions of a supercharger and apic of where it is in a marine engine. ive seen them in cars. i was thinking of a blower when you first said supercharger.

Tweak the 4.3 and have something different. Its a very strong motor and works better in your boat than a small block does. Theres a fair amount of products available for it. Although I'm not so sure you need through hulls. I had a 350 mag in my '96 21' Baja and switching between through hub and through hulls at WOT made NO change in speed or rpm's. Don't spend more than you have to. I have a cast iron single plane intake for your motor, pretty big runners no EGR Iwould sell for $50+shipping if you go that route. Get Desktop Dyno, Accurately put in your stock specs, make sure the hp is correct, then start tweaking and you will know where to put your $$.

If i did modify the 4.3, what cfm carb would I need (holley). I have heard when switching to thru hull, to gain top end, you need to get a new camshaft to see a difference in top end. Whats desktop dyno? where can i get one and how much do they cost?

I would probably use a 650 Demon. I know the theory of free flowing exhaust, but you only see improvement if the original exhaust is restricted enough to decrease engine output. If a 280 pshp 350 shows no change running through the prop, why spend the money? Although a 4.3 does sound pretty cool with through hulls!:p You need a cam that maximizes the efficiency of your carb,intake , heads, compression ratio, and exhaust.
Desktop Dyno is a dyno simulator that is accurate IF you put in the right info. Read the "Desktop Dyno question for D. Moore" thread in this section. I bought mine from www.summitracing.com, it cost $47.95 including the handling charge(which covers the "free" shipping) . Simulations on this program have saved me $800 per motor in parts I thought I needed but really only help slightly.