Author Topic: Carb and long tube headers for a stock 454 in a '75  (Read 1914 times)

Offline Powerhouse

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Carb and long tube headers for a stock 454 in a '75
« on: January 21, 2021, 03:43:16 PM »
Hello, I'm recently into a '75 C20 with a 454, and stock carb, 83,000 original miles, with no motor work.  It has been a daily driver so far, but I am starting to have issues with the carb and the headers are almost shot.  I am looking into doing a carb replacement, manifold, and possibly some long tube headers.  I am pondering what type of performance gains are on the table with these changes and what combinations someone can recommend.

Thank You,

Offline VileZambonie

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Re: Carb and long tube headers for a stock 454 in a '75
« Reply #1 on: January 21, 2021, 04:21:03 PM »
You may not be happy with the results from an intake and long tubes without doing any other modifications. In fact you may notice a reduction in throttle response and torque. Think about the whole package. If you aren't doing a cam swap, a dual plane intake manifold & shorty headers. What carburetor is on it now? Is the engine stock?
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              ⌠ŻŻŻŻŻ'   [☼===☼]
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Powerhouse

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Re: Carb and long tube headers for a stock 454 in a '75
« Reply #2 on: January 21, 2021, 05:00:02 PM »
Thank You Vile for the info. I want to make sure I try to do this once only, and the right way.

It is a bone stock engine & carb. 

My Ideal choice would be to do a cam, heads, manifold, carb, & headers all together to get the most out of the stock 454. The engine has relatively low miles on it, so the crank should be solid.  I was hoping I could do the work in stages, but if it isn't best to go like that I can leave well enough alone until I get the funds to do it all @ once.

I was wondering if I could do the carb, manifold, & header upgrade now, & those parts would be compatible with the heads & cam later.

Offline VileZambonie

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Re: Carb and long tube headers for a stock 454 in a '75
« Reply #3 on: January 21, 2021, 05:36:45 PM »
I would suggest you do the engine upgrades all at once. If your headers are crap, upgrade the headers and exhaust and rebuild the carburetor now. Save the engine rebuild for when you are ready and have everything you want to do the job right.
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Powerhouse

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Re: Carb and long tube headers for a stock 454 in a '75
« Reply #4 on: January 21, 2021, 05:51:51 PM »
OK Thank You.   What would be your choice for headers?

Offline VileZambonie

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Re: Carb and long tube headers for a stock 454 in a '75
« Reply #5 on: January 23, 2021, 06:27:25 AM »
For all out performance I use the biggest long tube headers. For best overall performance and reliability, I prefer shorty headers. Choose a set that is ceramic coated or stainless with thick flanges and solid connections. Cheap headers are more trouble than they are worth.
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Powerhouse

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Re: Carb and long tube headers for a stock 454 in a '75
« Reply #6 on: January 23, 2021, 02:31:03 PM »
OK Thank You. I appreciate the knowledge.  Based on those options I would rather go with reliability and overall performance.