Port & Polishing 4.3LX
 

I'm getting started on my "new" engine. Torn down and ready to hit machine shop for boring work.
Anyway , has anyone done any porting or polishing on the 4.3 swirl port heads. I'm thinking about a little massage work and just wondering if anyone has done them before and if so , was there any improvement at all.
I know they are notoriously a bad flowing head:(
Thanks for any input :)

Re: Port & Polishing 4.3LX
 

This will be one for the 'gear heads' around here. :)

If you are talking about the heads that have the ramp looking swirled port under the intake valve......yes I've played with the v8 version. Waste of time. If you are keeping them, best thing you can do is make sure they have a good valve job done on them and a new set of springs. Alot of "port and polish" work that is done actually hurts performance. Remember you want a strong torque producing engine, not a high rpm horsepower one. I'd make my power with a good cam, and bump up the compression. You'll be pleasantly surprised. :)

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Re: Port & Polishing 4.3LX
 

I would agree. more lift and duration, strong valve springs (meaning, test em all and replace any that are weak), more compression

Re: Port & Polishing 4.3LX
 

How much additional compression can that 4.3 handle?

Re: Port & Polishing 4.3LX
 

My machinist told me to not go more than 9.5 to 1. Need more cam for anything more and not a lot of selection for cams that are idle to 5000 rpm either. Cam overlap also comes into play.(Bad news for a marine engine) Also I was told that the press in rocker studs will only take up to .480 lift , after that got use screw in studs.
I have Silvolite 9.0:1 , .030 over pistons to go in it , and am planning on milling the heads to get to my 9.5:1 goal.
And yes , I thought about a V8 instead. But I don't want the extra weight or the loss of the good fuel "mileage" that the 4.3 has , not to mention the gearing issue.:)

Re: Port & Polishing 4.3LX
 

.030 over should get you close to the .5 compression ratio your looking for. However, there are several cams that offer way better performance and retain good fuel consumption. finding one that will pull hard right up to your desired max rev you want to run will be the key

Re: Port & Polishing 4.3LX
 

What cams did you have in mind? I haven't looked a lot , but seems there aren't many out there for the 4.3 that are torque oriented.

Re: Port & Polishing 4.3LX
 

Here is what I'd use. You won't be disappointed with any camshaft they make. I used them exclusively for all the race engines I built.

Re: Port & Polishing 4.3LX
 

Can u get away with just changing the camshaft? Will you still realize some significant gains?

Re: Port & Polishing 4.3LX
 

Forgot to mention , My 4.3 has a roller cam.
Here is the specs

CAMSHAFT SPECIFICATIONS:
Cam Lift (Int./Exh.): .269/.273

Valve Lift (Int./Exh.): .404/.410

.050" Duration (Int./Exh.): 202/213

Re: Port & Polishing 4.3LX
 

$143 and 10 for shipping sounds like a really good deal... The cam in my 450F cost a lot more than that...

Re: Port & Polishing 4.3LX
 

I'd be all over it , but it isn't a roller cam.:( The rest of my valvetrain is roller setup(lifters , pushrods , roller rockers , etc)

Re: Port & Polishing 4.3LX
 

Performance Camshafts, Lifter Kits and Matching Valvetrain for 6-Clylinder Chevy - Edelbrock.com

Products > Automotive > Camshafts > Ch. 4.3L 90D V6 92-02

Engle Racing Cams

Re: Port & Polishing 4.3LX
 

Thanks for the info Oregon. I'll check em out :)

If its a roller cam, yes. Changing from a stock shaft to something aftermarket is probably one of the best and biggest things a person can do to increase performance.
Compression wise 10:1 pistons are doable pretty easy as deck clearances, head gasket thickness, and head combustion chamber volumes are usually all greater than advertised. Another thing to remember is if you put a bigger camshaft in you may have 10:1 but with valve overlap it may have an effective ratio of only 9:1.


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Re: Port & Polishing 4.3LX
 

I wish Lunati had the VooDoo cams in roller configuration!

They do.
Part #20090720 is a good one.

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Re: Port & Polishing 4.3LX
 

Thanks for all the info guys :)
Decided to shy away from porting the heads and I went with the Edelbrock 3714 cam since I am already running the Edelbrock 2111 intake.

Edelbrock #350-3714
Rollin' Thunder Hydraulic Roller Camshaft
Chevy 4.3L 90° V6
.479''/.488'' Lift
272°/276° Adv. Duration
Idle-5500 RPM Range

Thanks again for all the great info!
I'll post what happens when I get it finished and back in the water come spring.

Re: Port & Polishing 4.3LX
 

great choice. But Im with ya...I hate it. It's winter, the time you want to do upgrades and changes, then you gotta wait til spring to test your results.

Re: Port & Polishing 4.3LX
 

I know......it's a catch 22 situation. If you do stuff in the summer you lose water time , if you do it in the winter you drool til spring to try it out.
Ahhhh , the life of a boater. :)

Re: Port & Polishing 4.3LX
 

unless you live on San Diego, Havasu, Corpus Chriti or Miami....then its party time everyday

Re: Port & Polishing 4.3LX
 

Yeah ,
I'm telling you now..........I ain't livin in Colorado for ever. LOL
Gotta go somewhere warm when I get older for sure.

Re: Port & Polishing 4.3LX
 

Yeah ,
I'm telling you now..........I ain't livin in Colorado for ever. LOL
Gotta go somewhere warm when I get older for sure.

Re: Port & Polishing 4.3LX
 

It was 75 degrees in central Alabama today, but I have covered mine for the winter,watching and learning from all of you, will be hunting a 4.3 soon. Bar