help I'm gonna build an engine

[2kvert]

Hey Guys
it seems my 97 4.3 is DOA
I have another donor engine to build and if im doing so Id like to build a bit more power into it.
thinking maybe more cam, an aluminum intake and ( is a 4bbl overkill ?)
also, is an hei distributor a doable or helpful swap? im not familiar with the distributor that is in the boat now with the module piggybacked behind it.
It seems like I had seen some build info in here before but I am not finding it now.
any advise or opinions are appreciated
thanks

 

[achris]

The vortec 4.3 is already on the raggedy edge of reversion. Any more cam will see it suck water in through the exhaust. If you go to an aluminium intake, you'll need to use a marine version. They have brass inserts in the water passages.

A 4bbl carb is a good addition. The Edelbrock 1409 fits these engines very nicely.

The current ignition system (Thunderbolt V) is about the best marine ignition system you can get. Stay with it. Run through the stickies, I have done a write up on it. Very easy to understand...

Chris...

 

[alldodge]

Don't know what distributor you have but if its a TB or EST your good, my 530HP 509 uses the EST

Being a 1997 it should be a TB5 and your good
Yes use a 4bbl, but unless your closed cool or in fresh water stay clear of aluminum intake

Hey Scott Danforth

 

[tank1949]

The vortec 4.3 is already on the raggedy edge of reversion. Any more cam will see it suck water in through the exhaust. If you go to an aluminium intake, you'll need to use a marine version. They have brass inserts in the water passages.

A 4bbl carb is a good addition. The Edelbrock 1409 fits these engines very nicely.

The current ignition system (Thunderbolt V) is about the best marine ignition system you can get. Stay with it. Run through the stickies, I have done a write up on it. Very easy to understand...

Chris...

I've performed conversions similar to what boater is contemplating: more power. In my case I went from 250 inline Chevy 6 cyl to 350 V8. The bolting of transom assembly was about the easiest part of the job and then the nightmares came of new ignition/ exhausts and motor mounts needed. If I remember correctly, I had to also buy a new prop. I finally got it working and it provided a great increase of performance but it was not cost effective. Edelbrock makes a damn good 4 barrel. I don't know if automotive machine shops can make a 4.3 into a stroker version?

 

[Scott Danforth]

there was a 4.3 build a few year back by Tail_Gunner https://forums.iboats.com/forum/eng...utdrives/301413-4-3-vortec-build-up-and-traps

reversion is real and the 4.3's were on the edge. the 220hp MPI is about 250hp at the crank. its held on the edge by the knock sensors....

225hp at the crank is very doable with the 4.3 and a 4-barrel carb (its what the motor was producing back when they called it 205hp (at the prop)

your existing dizzy is fine, why flush money away
a 4-barrel carb is highly recommended.
if you go with dry jacketed exhaust, you can go crazy with the cam and get more...... however that would cost you more for the exhaust than it would for the motor
if you are building new motor, you can go with HX cooling. or there are plenty of dual alloy intakes (aluminum with bronze water passages)

if your boat was also sold with a V8, I would seriously look to migrate to a 5.7 vs dumping money into a 4.3. not only is the motor cheaper then the 4.3, it makes lots more power

 

[achris]

I've performed conversions similar to what boater is contemplating: more power. In my case I went from 250 inline Chevy 6 cyl to 350 V8....

That's not what he's contemplating. He has a 4.3, and is inquiring about building up another 4.3. Apples and oranges.

Chris....

 

[2kvert]

Thank you all. This was a big help.

 

[tank1949]

That's not what he's contemplating. He has a 4.3, and is inquiring about building up another 4.3. Apples and oranges.

Chris....

But, I'd bet it is in the back of his mind. And, perhaps he doesn't know that he can "stroke" a 4.3? Smells like apple sauce to me. https://www.hotrod.com/articles/hrdp-0705-pitstop-chevrolet-v6-performance/