4.3 vortec

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rcm243
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4.3 vortec

Postby rcm243 » Tue Sep 09, 2014 5:52 pm

I`ve got a 4.3 on my boat and it does perform to my satisfaction, it has a 4 barrel holley 450cfm and after tying off the secondary the engine still turns 2900 rpm DD. My question is, would a real 2 barrel carb make any difference in the performance as far as quicker throttle response? RCM
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Superduty88
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Re: 4.3 vortec

Postby Superduty88 » Tue Sep 09, 2014 6:25 pm

I went from a 650 edlebrock to a 500 2 barrel holley it mad a big difference that was on a sbc
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Alvarez1112
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Re: 4.3 vortec

Postby Alvarez1112 » Tue Sep 09, 2014 7:09 pm

I can't answer your question, but I have a 350 cfm two barrel Holley on my 4.3. I have excellent throttle response, but did fight a stumble at one point that mysteriously went away. I'd love to try a 390 4 barrel with the HP body, but can't see spending the money?
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Deano
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Re: 4.3 vortec

Postby Deano » Tue Sep 09, 2014 7:15 pm

A 450 Holley is a real good carburetor. However that doesn't change the fact that it's nearly twice as big as it needs to be on that engine running those RPMs. Not really a surprise the secondary's are of little value.

I've only been around one V6 DD and ran it better with a 350 Holley than anything else he tried. The 350 is basically the same as the 500, it's just smaller. If it were me, that is what I would run.

To answer your question, I would say YES . . . as long as it's properly jetted.
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spooledup50
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Re: 4.3 vortec

Postby spooledup50 » Tue Sep 09, 2014 10:37 pm

I had a 380cc 4 barrel holley on mine and it loved it
350ci wiskey drinking son of a b&$@ch.....E85!


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spooledup50
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Re: 4.3 vortec

Postby spooledup50 » Tue Sep 09, 2014 10:38 pm

380cfm autocorrect
350ci wiskey drinking son of a b&$@ch.....E85!

rcm243
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Re: 4.3 vortec

Postby rcm243 » Tue Sep 16, 2014 6:19 pm

Deano wrote:A 450 Holley is a real good carburetor. However that doesn't change the fact that it's nearly twice as big as it needs to be on that engine running those RPMs. Not really a surprise the secondary's are of little value.

I've only been around one V6 DD and ran it better with a 350 Holley than anything else he tried. The 350 is basically the same as the 500, it's just smaller. If it were me, that is what I would run.

To answer your question, I would say YES . . . as long as it's properly jetted.
I just got a carter 2 barrel carb and it seems to be in good shape, there`s a number on the carb, 4895s and the alum. tag has 2076 on it, would this be worth a try? RCM
Politicians are like whores,as long as the money`s available they`re there for you.

rcm243
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Re: 4.3 vortec

Postby rcm243 » Fri Sep 19, 2014 5:23 pm

rcm243 wrote:
Deano wrote:A 450 Holley is a real good carburetor. However that doesn't change the fact that it's nearly twice as big as it needs to be on that engine running those RPMs. Not really a surprise the secondary's are of little value.

I've only been around one V6 DD and ran it better with a 350 Holley than anything else he tried. The 350 is basically the same as the 500, it's just smaller. If it were me, that is what I would run.

To answer your question, I would say YES . . . as long as it's properly jetted.
I just got a carter 2 barrel carb and it seems to be in good shape, there`s a number on the carb, 4895s and the alum. tag has 2076 on it, would this be worth a try? RCM


After trying the carb mentioned above, I`ll have to say that it is performing much better than the 4 barrel, the motor picked up 200 more rpm and the throttle response is much better, needless to say I`ve got a holley 450 cfm that I don`t need anymore. RCM
Politicians are like whores,as long as the money`s available they`re there for you.

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John Fenner
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Re: 4.3 vortec

Postby John Fenner » Thu Dec 25, 2014 9:53 am

Just built a 4.3 setup for a guy, used the TBI intake, adapted a monojet to it, took out main jet about .012" idle circuit about .006" and accelerator squirter about same as the idle circuit, responds nicely, turns 71" sensenich 2950 at #1 on trailer.
I never finish anyth,,,.

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spooledup50
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Re: 4.3 vortec

Postby spooledup50 » Tue Dec 06, 2016 7:50 pm

I used to have a very good running 4.3 , I used a 390cfm Holley with manual secondary not a double pumper it was single feed 4160 style 62 jets in the front ran excellent


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