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.

I will look for that program. If I have a few hundred extra, I'll put the thru-hull on.

Where could I find a pro charger for it?

Problem NO ones Silent Choice, Quick & Quit, or Captians Call totaly seals of the transom exhast air tight. Ya most of it goes, out the prop, but a performance engine has a lot of presure being made at 5000 rpms and my freinds Fountain with a 454 carbed mag motor and a pro-charger see's almost 100 rpm's when he swiches his exhaust. And that is on his gafrig gauge. Charlie

here you go it is off NW Jim's site

Marine M 1 intercooled Pro Charger Holly carb complete system. This is truely a rare opportunity for those of you looking at getting that extra power out of your motors. I have two of these, but am separating for the auctions. I have replaced my whole system in my boat and you are the lucky ones to get this opportunity to purchase this complete system. This system consists of a M-1 Carb, Intercooler, complete with Pro-charger, marine Holley carb, K&N Filters with all of the parts and accessories to install. These go for around $6800 dollars and I do not think these will last long.
$3850.00
Call 253-261-3717, 253-638-9540 or
Email: [email protected]
<-08/01/02->

DAMMIT!!!! i need 4 k......

Is there something I could do to add a mph or two for free? im taking all the extra crap off of it soon, less weight and what about advancing ignition, it is at 12 deg Before TDC (yes, i do know what that means) is advancing ignition hard or is it a few min task?

The 4.3 has some really crummy heads. The problem is that nobody makes a better one, so you're stuck. You do have a roller cam which is good, but you still won't make good power without some good heads. Vortech does make a carb box that will fit the 4.3. Most of the systems that are designed for a small block should fit the 4.3 with only some minor modifications. In all honesty though, I'd be looking at a 144 holley/weiand supercharger. They are very affordable (about $1,800) and will give a 35-40% boost in power. That'll put you right around 350hp. After that you'll be looking for ways to improve your alpha. Besides, scoops are cool.

BTW-there is a scoop that will just bolt onto your hatch. You carefully peel back the vinyl, cut your hole, then wrap the vinyl back over the edge and staple it. The effect is clean for very, very little cost. By far the most expensive part is the scoop ($350) and you will still be money ahead because the supercharger is so much cheaper.

Vortech heads for 4.3?
 

Didn't Chevy make a vortech version of the 4.3? I know that I have seen this engine listed for the S10 Blazers. Come to think of it, I saw a set of these heads at a swap meet a few years back. Seems like they had the swirl-ports, bigger valves, etc. Does anyone know if these have the same cobustion chamber/port design as the vortech heads for the 5.7L? These are supposed to be some really good heads for the V-8's, and if you could get a set for the 4.3 at a salvage yard, then do a little valve bowl work, maybe add some larger valves, you would be in business. As was mentioned before, the 4.3 is essentially a 5.7 with two less cylinders. They will respond to the right modifications. Just ask anyone who is associated with the Busch Grand National circuit!

Maybe Dennis Moore could chime in on this one. It could be an interesting project.

So if i cant find a part for the v-6 (ex pistons or connection rods) i could buy the ones for the 350 then have 2 extra?
On that supercharger- would stock internals be fine?

The only parts from a small block that won't fit are the heads, intake and crank. Everything else exchanges.

UUUH oh.....
 

Went down to it yeaterday, started it an got a belt squeak. no prob, open the hatch, loosen alternator and slide it out till belt is tight.

BUT. Back of alternaor slide has a good amount of oil on it, how big are the chances of a bad oil pan gasket on a 1990?

AND. loosening alternator wouldnt have done much, it is where the slide screws into the block. this has come out 2times in the past month (only 2 times it has happened though) , how do i stop it from coming out?

This Kid is dreaming right now , cause this is dads boat
and he's 15 years old, I guess its good to dream:D :D

I do it too! 36 skater??? yes it would be nice but out of my range

So you are saying there is a certin age you have to be before you are alowed to have the want to make something go faster than it does when it is stock?:confused:

I would the dreaming part is great it too bad you cant allways
do everything to your boat that you want.
I think we all could spend a ton of money if we had it


Im assuming that it's the Kids fathers boat right I see from
the profile that he's one of the youngest Posting members.
well at least when he's my age He will be a expert from all
the thing's he going to learn here.

Yeah, working age to get the $$$$ to buy the parts to go faster. We all know how much that costs:rolleyes:

mopower,just imagine working for a long time, then getting a pay check enough to put gas in the boat and save some for mods.... well, i have a styrofoam cup here with the words "super charger fund" written on it and am going to the marina to beg for money for a supercharger....



yes it is my dads boat, but ( :D ) he has been on it maybe 3 times this year and we have a season wet dock and i have a boaters license so i can take it out without adult supervision :D

HB ,
Give me your address and I'll chip in $10:D :D . Anybody willing to go beg for a s/c certainly wants it bad enough:D :D

LOL Awesome!!! Ill pm it to you! im still laughing!!! LOL. To bad no one was at the marina to beg money from so i just cleaned the boat instead.