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Old 11-05-2012, 06:22 PM   #1
zombiescustoms
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Tired of TBI issues, what size carb???

I have a 1987 one ton, with a 454 turbo 400, mild RV/ towing cam with TBI problems, and I'm tired of throwing money at it! So I'm going with a carb and intake set up and a fuel regulator to use the stock electric pumps. I'm going to be using the weiand 8017 manifold but need to know what size carb I should use, I have a 585 CFM Holley from my 327CI but I'm thinking im going to need at least a 650, any suggestions??

It will also have a MSD dist. and box, and a set of small dia primary headers.
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Old 11-05-2012, 08:58 PM   #2
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Re: Tired of TBI issues, what size carb???

i have a stock 95 454 with the peanut port heads going in my 86 soon. i have done a lot of reseach with what carb to use and came up with the street demon 625. with your build being very simular, you just adding a mild cam, a 600 to 650 should work well
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Old 11-05-2012, 09:59 PM   #3
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Re: Tired of TBI issues, what size carb???

Buy a quadrajet. They work great on 454 powered trucks. Small primaries for economy and big ass secondaries for passing.
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Old 11-05-2012, 10:27 PM   #4
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Re: Tired of TBI issues, what size carb???

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Buy a quadrajet. They work great on 454 powered trucks. Small primaries for economy and big ass secondaries for passing.
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I second that.
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Old 11-05-2012, 10:40 PM   #5
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Re: Tired of TBI issues, what size carb???

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Buy a quadrajet. They work great on 454 powered trucks. Small primaries for economy and big ass secondaries for passing.
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I'm sure he wants something just to throw on there and forget not fiddle with for weeks to months to get it to run right. What you guys thinking about "economy" on a 454 joking with you guys haha

For your towing I would recommend a vacuum secondary holley 600-650
Regulate to 6psi and a distributor that's not computer controlled.
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Old 11-06-2012, 02:26 AM   #6
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Re: Tired of TBI issues, what size carb???

Just my humble opinion, but my guess is you'll be a lot more tired of that carb in time. Sounds like you just need a new TBI unit from someone like Holley or something.
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Old 11-06-2012, 06:26 AM   #7
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600 cfm is fine for a bb you could run a 750 but no real need to. either way your going to give the engine more air then a stock 2bbl tbi would. it still amuses me that it must have been a huge secret or some thing but ford 460's pre fuel injection ran 600 cfm carbs from the factory and man could they run.


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Old 11-06-2012, 07:36 AM   #8
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Re: Tired of TBI issues, what size carb???

Most TBI operation problems are caused by poor fuel pressure.
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Old 11-06-2012, 09:18 AM   #9
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Re: Tired of TBI issues, what size carb???

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Just my humble opinion, but my guess is you'll be a lot more tired of that carb in time. Sounds like you just need a new TBI unit from someone like Holley or something.
I'm with this guy...quit throwing money at your TBI And do some diagnostics to figure out your problem! The TBI system is simple and works well!
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Old 11-06-2012, 07:26 PM   #10
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Re: Tired of TBI issues, what size carb???

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Buy a quadrajet. They work great on 454 powered trucks. Small primaries for economy and big ass secondaries for passing.
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the demon 625 i mentioned hasthe small primaries a a sigle huge sinle secondary. heres a link
http://www.demoncarbs.com/1900.asp
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Old 11-06-2012, 07:39 PM   #11
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Re: Tired of TBI issues, what size carb???

(1) more vote for the quadrajet.
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Old 11-06-2012, 07:45 PM   #12
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Re: Tired of TBI issues, what size carb???

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the demon 625 i mentioned hasthe small primaries a a sigle huge sinle secondary. heres a link
http://www.demoncarbs.com/1900.asp
Is there any aftermarket carb company like that, that finally defeated to cold start issue? That's my one of my many complaints about carbs. When its cold outside, carb'd engines don't like to start.
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Old 11-06-2012, 08:14 PM   #13
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Re: Tired of TBI issues, what size carb???

with a good operating choke/carb, you shouldn't have any issues. the quadrajet on my old k10 would fire the engine even at -10*. what is "cold weather" to you?
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Old 11-06-2012, 08:20 PM   #14
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Re: Tired of TBI issues, what size carb???

http://www.summitracing.com/parts/DEM-1900/?rtype=10

Street Demon

625 EFI carb and it is budget friendly too. From the ads I have read it installs in 30 minutes and has one wire 4 bolts and no laptop or computer to tune it.
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Old 11-06-2012, 08:32 PM   #15
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Re: Tired of TBI issues, what size carb???

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with a good operating choke/carb, you shouldn't have any issues. the quadrajet on my old k10 would fire the engine even at -10*. what is "cold weather" to you?
Well im in texas so to me cold weather is around 10*, to about 35*. Typically that's what you see around here. But my quadrajet on my 82 (newly rebuilt) hated anything below about 30 so I guess anything below that temp I would consider "cold" when it comes to this. I've also had a couple other carb'd vehicles that were the same way. Though I no longer own any of them. Went with TBI lol. Seemed like every carb I've ever owned was just trouble waiting to happen if it wasn't already happening. That's why I always just recommend fuel injection cause it ditches the long list of problems that carbs eventually have. Just my personal experiences i guess.
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Old 11-06-2012, 08:35 PM   #16
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Re: Tired of TBI issues, what size carb???

i rebuilt the carb on my pickup when the cam went flat at 88k miles, it was still going strong 10 years later when i sold it, and it didn't live an easy life.
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Old 11-07-2012, 07:20 AM   #17
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Re: Tired of TBI issues, what size carb???

Tear down an old carb'd engine, then do the same to a TBI or MPFI engine. Difference in cylinder wear will make you a TBI fan, quick. All the older blocks I tear down have a significant ridge at the top of the bore from wear...almost every TBI or MPFI engine I've torn down still has visible hone marks in the bores. A small part of this is due to lighter ring pressure against the cylinder walls, but the majority is the TBI. With a decently tuned TBI, you never get fuel wash down the cylinder walls, you never flood out, your engine is metered fuel as it needs it and it's monitored by the O2 sensor.
And you can get a TBI harness that will let you run a 4L80E tranny for around $300. That in itself would weigh heavily on my decision. I'm converting an '85 1-ton dually to TBI for just these reasons.
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Old 11-07-2012, 07:28 AM   #18
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Re: Tired of TBI issues, what size carb???

I hope that I have figured out the problem, my Speedo is not working! So no Vss signal going to the ecu causing the lean stumble/ surge, I think it may be the gear in the trans. Man I hope this fixes it!
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Old 11-07-2012, 08:27 AM   #19
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Re: Tired of TBI issues, what size carb???

sounds like your truck needs to go to a reputable shop and get fixed correctly.
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Old 11-07-2012, 05:15 PM   #20
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Re: Tired of TBI issues, what size carb???

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Tear down an old carb'd engine, then do the same to a TBI or MPFI engine. Difference in cylinder wear will make you a TBI fan, quick. All the older blocks I tear down have a significant ridge at the top of the bore from wear...almost every TBI or MPFI engine I've torn down still has visible hone marks in the bores. A small part of this is due to lighter ring pressure against the cylinder walls, but the majority is the TBI. With a decently tuned TBI, you never get fuel wash down the cylinder walls, you never flood out, your engine is metered fuel as it needs it and it's monitored by the O2 sensor.
And you can get a TBI harness that will let you run a 4L80E tranny for around $300. That in itself would weigh heavily on my decision. I'm converting an '85 1-ton dually to TBI for just these reasons.
Ultimate replacement for carbs. Carbs had their time, now its over. I personally can't understand the attachment that some people have to them. They're antiques! Good for looking at and saying "Oh, that's how they used to do things? Oh ho ho ho ho ho!!"

Flame suit on! LOL
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Old 11-07-2012, 05:48 PM   #21
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Re: Tired of TBI issues, what size carb???

Good news, the truck is running perfect now, the 90deg Speedo adapter was shot, hooked the Speedo cable directly to the trans, and all is good! I had no idea that these early trucks had the vss sensor in the Speedo itself. Glad I did not blow all the money on a carb set-up
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Old 11-07-2012, 07:57 PM   #22
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Re: Tired of TBI issues, what size carb???

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Is there any aftermarket carb company like that, that finally defeated to cold start issue? That's my one of my many complaints about carbs. When its cold outside, carb'd engines don't like to start.
Man, I've lived in places that get to -40 and carbs was all we had. They started then.
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Old 11-07-2012, 09:26 PM   #23
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Re: Tired of TBI issues, what size carb???

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Originally Posted by BigBlocksRule View Post
Tear down an old carb'd engine, then do the same to a TBI or MPFI engine. Difference in cylinder wear will make you a TBI fan, quick. All the older blocks I tear down have a significant ridge at the top of the bore from wear...almost every TBI or MPFI engine I've torn down still has visible hone marks in the bores. A small part of this is due to lighter ring pressure against the cylinder walls, but the majority is the TBI. With a decently tuned TBI, you never get fuel wash down the cylinder walls, you never flood out, your engine is metered fuel as it needs it and it's monitored by the O2 sensor.
And you can get a TBI harness that will let you run a 4L80E tranny for around $300. That in itself would weigh heavily on my decision. I'm converting an '85 1-ton dually to TBI for just these reasons.
No no and no. Lol tbi engines mostly had over drives which reduced wear massively and the engines started sooner and warmed up quicker further reducing wear. Fuel wash is a very small part

As for cold starts in carbs. Why is it that my holley with no choke horn and engine with lopey cam can start right up in 20*f weather in Washington and I haven't touched my carb since I first tuned it three years ago when I first installed the engine in July! Because i put some effort into understanding how a holley works and tuned it accordingly. So only expect as much gain from your carbs guys as you put into them. A tuned carb still kicks a computer in power all day
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Old 11-07-2012, 09:37 PM   #24
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Re: Tired of TBI issues, what size carb???

bigblocksrule, if an engine is having fuel wash issues(like you are describing), the carb is way out of tune, way too rich. you can get the same fuel wash with a fuel injected engine. i had a friend do a 5.3 swap into a g-body, cam, heads, headers, different injectors, etc. his mail order tune was rich and he washed the rings out.....with mpfi. it's all about the tune, just as insidious talked about.
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Old 11-07-2012, 10:23 PM   #25
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cool glad it was an easy fix 20 bucks compared to 500 is always nice in my book. as far as engine wear issues has nothing to do with induction its more of a modern materials used in newer engines and modern oil.


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