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-   -   Building up a Vortec 4.3 (https://www.offshoreonly.com/forums/do-yourself-boating-budget/238098-building-up-vortec-4-3-a.html)

speedboatr 09-07-2010 09:50 PM

Hi Guys,

Thanks for the info. The brothers that own the machine shop had the same to say about the motor. Sounds like it can be done but will be costly and that reversion thing…… dose not sound like fun. Think I’m going to keep it close to stock and use it to move to a larger boat next spring.
Thanks,
Speed.

speedboatr 09-09-2010 10:38 PM

Anyone know the stock cam specs??

fkboatman 09-09-2010 11:03 PM

my brother is building one now for a customer, hang tight till tomorrow will get you all info.

speedboatr 09-10-2010 05:03 PM

Ok guys,
Looks like it’s coming down to up grading the cam or keeping the stock one. Here is what I have so far.
1997 4.3 vortec , (started life as a 225HP motor, not sure if that maters) pistons are now 60 over, Edelbrock Performer Intake and marine series 600 CFM Carb. Would adding a mild cam over the stock cam make much of a difference without the heads and valve work I keep reading about?

Thanks,
Speed

BUIZILLA 09-10-2010 06:43 PM

you could go to 1.6 Pro Magnum rockers and use the stock cam.. I don't think many cam companies stock 6 cyl blanks, unless Bullet or Crane have them.. you can get COMP to custom grind one from their blanks if you know the lobe profiles you want.. the Brodix heads would really wake it up..

speedboatr 09-11-2010 08:25 AM

the heads would be great, but trying to do this without putting much $$ into it. i have to add the intake and carb (previous owner lost them??) but the more i look around is sound like the cam alone will not do much so I may stick with the stock one.

Thanks,
Speed

BUIZILLA 09-11-2010 08:40 AM

let's see what fkboatman comes back with.... :)

in your case just the intake, carb, IMCO exhaust, and 1.6 rockers would be it.. make sure you get the non guide plate rockers...

jeffswav 09-12-2010 09:12 AM

Do not change the cam without first getting aftermarket exhaust with long risers. Reversion will kill it real quick.

HaxbySpeed 09-12-2010 10:47 AM

Even the stock ones have reversion issues. They are a tough little engine though.

Baja_man 10-01-2010 05:37 PM

I have onlt seen one company that makes exhaust for the 4.3...
http://www.imcomarine.com/ca_store/i...roducts_id=805

I looked into this same thing 6-8 years ago and found it way to expensive to get any real gains from it. You will be much better off getting a used 350 or even a 454 and keep those stock and still have more HP than you could ever get out of a 4.3.


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