Carb replacement recommendation?

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j-rad

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Dec 30, 2024
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Location
CT
First Name
jared
Truck Year
1986
Truck Model
K10 Stepside
Engine Size
383
Have a Blueprint Engines 383 stroker with 750cfm carb currently. Looking to replace the carb with something with an electric choke.

Was considering the Holley 670 street avenger. A little better fuel economy would be nice and not worried about the performance hit. Is this a good carb, and is it worth going down to a 670 or should I stick with a 750?

It’s more engine than I need and would like a better casual driving experience without a full engine swap, if this will help.
 

Grit dog

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Todd
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1986, 1977
Truck Model
K20, C10
Engine Size
454, 350
Have a Blueprint Engines 383 stroker with 750cfm carb currently. Looking to replace the carb with something with an electric choke.

Was considering the Holley 670 street avenger. A little better fuel economy would be nice and not worried about the performance hit. Is this a good carb, and is it worth going down to a 670 or should I stick with a 750?

It’s more engine than I need and would like a better casual driving experience without a full engine swap, if this will help.
Wish we were closer in could trade you up to a new 350 with electric choke that is a much more causal driving engine. Think she makes about 179 hp. Because I’m about 1 hp loss from sea level due to altitude, lol!
Sorry don’t have any carb advice.
 

j-rad

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jared
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1986
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K10 Stepside
Engine Size
383
Wish we were closer in could trade you up to a new 350 with electric choke that is a much more causal driving engine. Think she makes about 179 hp. Because I’m about 1 hp loss from sea level due to altitude, lol!
Sorry don’t have any carb advice.
This thing is a beast. Considered a swap to a 350 but with all the body work it needs, figure I’ll embrace it for a while.
 

Ricko1966

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kansas
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1975
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c20
Engine Size
350
Have a Blueprint Engines 383 stroker with 750cfm carb currently. Looking to replace the carb with something with an electric choke.

Was considering the Holley 670 street avenger. A little better fuel economy would be nice and not worried about the performance hit. Is this a good carb, and is it worth going down to a 670 or should I stick with a 750?

It’s more engine than I need and would like a better casual driving experience without a full engine swap, if this will help.
Find out what cam is in it,cam swap very likely could bring it more to your liking. As for carb you don't need to stay 750 for your usage somewhere in the 650 range with vacuum secondaries will work nice. Big engines can be silky smooth and extremely user friendly,no reason to do an engine swap.
 

j-rad

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jared
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1986
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K10 Stepside
Engine Size
383
Find out what cam is in it,cam swap very likely could bring it more to your liking. As for carb you don't need to stay 750 for your usage somewhere in the 650 range with vacuum secondaries will work nice. Big engines can be silky smooth and extremely user friendly,no reason to do an engine swap.
Believe it’s the below:

Camshaft: Hydraulic Roller Cam - .544 Intake / .555 Exhaust Lift and 230 Intake / 236 Exhaust Duration @ .050 - 110° LSA
 

Ricko1966

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Call comp cam,call blueprint and let's see if we can get @Mark Jones to weigh in on this if you are wanting to tone it down I'm thinking you need to drop the duration down in the 215/220 range bring lift down to about .500 and lsa widened up to more like 114 I think would give you smooth power from idle up. But talk to comp,talk to blueprint and talk to @Mark Jones .
 

75gmck25

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Bruce
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1975
Truck Model
K25 Camper Special TH350 NP203
Engine Size
5.7
The Edelbrock AVS2 gets a lot of good reviews for easy setup and good street manners. It is available in 650 or 800 cfm, and your engine and heads have the flow two use the larger carburetor. However, the 650 would also work fine.

I used a 213/217 @ .050 and 112 LSA cam in my 350 and it’s a very smooth running engine that is well-suited to a heavy vehicle like a squarebody. In the old days, cams with about 214-218 duration were referred to as RV cams because they provided more total power, but also kept low rpm torque. With your Blueprint heads it should work even better.
 
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