Quick fuel or not.

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Scoot454

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Thinking about a carb swap. I have a 750 dp Holley on my built up 454 and I feel like I should go a little bigger. The engine feels like it has a restrictor plate on it. It should perform better for the work that was put into it. Looking at Quick fuel 800 or 830. Any feedback is welcomed.
 

QBuff02

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I'm in a similar boat as you and also doing some research. But my 454 has a Demon 850 on it right now and I feel it's just a touch too much carb for my combo. And it's also a version before their idle-eze base plate came out, so with my cam it's been a little bit of a pain to tune down low. After doing some research and discussing with my engine builder, I'm leaning more towards a quick fuel slayer 750 if I decide to change carbs. I know I might give up a little on the big end, but realistically it's going to live below 4,500 probably 80% of the time or more. I'd sacrifice a little power for better driveability though, I can tell you that much. Trolling around your posts to see what you've got I see you have an MSD ignition as well, what do you have your spark plug gap set at and your timing set at? Initially I was losing some "rev" due to not having a low resistance bushing in the distributor and my plug gap set a little too tight..
 

hirschdalechevy

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Thinking about a carb swap. I have a 750 dp Holley on my built up 454 and I feel like I should go a little bigger. The engine feels like it has a restrictor plate on it. It should perform better for the work that was put into it. Looking at Quick fuel 800 or 830. Any feedback is welcomed.

If it was me I would start by going though the ignition first. Make sure you have enough total advance and check your curve , if that is not right your big block will be sluggish. I always do ignition first before any carb. adjustments. I am also not a fan of any ignition control boxes on mild street motors so maybe bypass the msd box and run her and see how she does.

With that being said , I just picked up a quick fuel off road carb. for my new motor and it is really sweet. Just fired the motor and it ran great out of the box. I am getting the exhaust done now so I have not made any adjustments to the quick fuel at this time.

What is nice about them is you can adjust everything , idle feed , idle air , etc...……. I am putting an o2 sensor in the exhaust with an afr gauge so I can tune it to perfection.

So I would say go though the ignition and maybe think about a afr , o2 set up and try a quick fuel carb.

I don't know your engine specs but a 750 cfm carb is not a bad choice for a mild bbc . Just remember that a carb. on the smaller side has better manners on the street and is easier to tune than a larger cfm carb for wide open , top end horsepower and most dyno runs show only small losses with a smaller cfm carb vs large cfm carbs on a most mild street engines and only on the top end , most of the time. For a drag car its a different story, (go big).
 

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What intakes are you running?
 

Snoots

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I'm running a 7161 Edelbrock Performer RPM on my 454.
It's great for a fishing sinker.
You're better off with a stock intake or, if weight is a concern a GM Chevy Performance intake.
 

QBuff02

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If it was me I would start by going though the ignition first. Make sure you have enough total advance and check your curve , if that is not right your big block will be sluggish. I always do ignition first before any carb. adjustments. I am also not a fan of any ignition control boxes on mild street motors so maybe bypass the msd box and run her and see how she does.

That's also why I asked about his timing, I've learned sometimes that's the initial problem that gets overlooked. Although I have to disagree with no MSD's etc on something like a "street" or mild performance engine. If they're set right (back to timing and advances) they sure help a heckuvalot on cold starts and down low rpm operation. At least in my experiences and what I've seen they do. Just curious what your thoughts are on that and why you're not a fan of them for that application?

[QUOTE/]With that being said , I just picked up a quick fuel off road carb. for my new motor and it is really sweet. Just fired the motor and it ran great out of the box. I am getting the exhaust done now so I have not made any adjustments to the quick fuel at this time.[/QUOTE]

Question- little different animal of a carb than I'm looking at, but what are your initial thoughts on quality, fit and finish of the quickfuel that you bought?

I don't know your engine specs but a 750 cfm carb is not a bad choice for a mild bbc . Just remember that a carb. on the smaller side has better manners on the street and is easier to tune than a larger cfm carb for wide open said:
^^^Pretty much the exact conversation myself and My engine builder had. And really not going to give up very much, at least what the ol' ass dyno will say! Lol

:driver:
[/QUOTE]
 

TravisB

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It's great for a fishing sinker.
You're better off with a stock intake or, if weight is a concern a GM Chevy Performance intake.
What's wrong with the performer RPM? I was reading a super Chevy article the other day where they made almost 50hp from a regular performer and headers on a small block and then it got even better with an rpm.
 

QBuff02

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It's great for a fishing sinker.
You're better off with a stock intake or, if weight is a concern a GM Chevy Performance intake.


I'm intrigued.. Everything runs good so far I think, and I've seen them on a lot of Big Blocks. I almost kept the old '65-'68 high performance factory Holley cast iron intake on it when I rebuilt it. But decided modern would probably be a better option. I've just never heard anyone come right out so against them.. Lol
 

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They tend to 'strangle' the engine. A lot of folks (me included) have blamed the carb (especially after an engine rebuild) when the intake, a Performer or especially an SP2P was used. They just don't flow well.
Got rid of the SP2P for a Performer (both Edelbrock) then, went to stock without touching anything else, problem solved.
More 'grab you by the seat of the pants' power and not nearly as sluggish off the line.

That's just my 2 cents. I don't have any numbers to prove otherwise and don't plan on pulling the engine and trying different intakes on a dyno. The 'feel' was good enough for me.
 

Scoot454

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It has a performer intake. This one was built for low end grunt for truck pulls but still streetable. It will rarely see 6500 rpm but I want it capable when I need it. I know there’s a local shop nearby that has a dyno. When I get it out of winter storage I’ll see if he can set me up and we’ll dial in the timing first. I think you all are correct about tweeking timing before I go to carb size. Thanks for the advice and I’ll let you know what happens.
 

QBuff02

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They tend to 'strangle' the engine. A lot of folks (me included) have blamed the carb (especially after an engine rebuild) when the intake, a Performer or especially an SP2P was used. They just don't flow well.
Got rid of the SP2P for a Performer (both Edelbrock) then, went to stock without touching anything else, problem solved.
More 'grab you by the seat of the pants' power and not nearly as sluggish off the line.

That's just my 2 cents. I don't have any numbers to prove otherwise and don't plan on pulling the engine and trying different intakes on a dyno. The 'feel' was good enough for me.


Man, that sucks. Thanks for sharing your experience. isn't that sp2p intake supposed to be like a "fuel minder" type design, I could see where an intake like that would just about cripple an engine. As far as the Performer RPM goes on my engine, I'm pretty happy with the way it runs, and it's snappy and crisp. My issue is the 850 Demon carb, it's just a little too "race" for my 10.25:1 468 that sees mostly street type driving. It's an animal when it's wound up, but it's pretty fat every where else in the curve. And that's where it lives majority of the time, so that's also why I'm considering downsizing just a tad. Something a little more "tuner friendly" for my particular application. Eventually going to go the route of fuel injection.
 

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Question- little different animal of a carb than I'm looking at, but what are your initial thoughts on quality, fit and finish of the quickfuel that you bought?

Not familiar with automotive QF carbs but know many who have used marine QF carbs in their boats.
Extremely high marks from virtually every one of them.
Billet throttle body's and metering blocks/plates, adjustable air bleeds, externally adjustable floats with site windows, externally adjustable secondaries and the list goes on. A good quality unit that is a Holley design but built like a Holley should be. Probably why Holley bought them out.
I personally wouldn't hesitate to buy one.
 

Snoots

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It has a performer intake. This one was built for low end grunt for truck pulls but still streetable. It will rarely see 6500 rpm but I want it capable when I need it. I know there’s a local shop nearby that has a dyno. When I get it out of winter storage I’ll see if he can set me up and we’ll dial in the timing first. I think you all are correct about tweeking timing before I go to carb size. Thanks for the advice and I’ll let you know what happens.

Cool! Be looking forward to the update.
 

hirschdalechevy

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That's also why I asked about his timing, I've learned sometimes that's the initial problem that gets overlooked. Although I have to disagree with no MSD's etc on something like a "street" or mild performance engine. If they're set right (back to timing and advances) they sure help a heckuvalot on cold starts and down low rpm operation. At least in my experiences and what I've seen they do. Just curious what your thoughts are on that and why you're not a fan of them for that application?

[QUOTE/]With that being said , I just picked up a quick fuel off road carb. for my new motor and it is really sweet. Just fired the motor and it ran great out of the box. I am getting the exhaust done now so I have not made any adjustments to the quick fuel at this time.

Question- little different animal of a carb than I'm looking at, but what are your initial thoughts on quality, fit and finish of the quickfuel that you bought?

[/QUOTE][/QUOTE]

I am not a fan of msd control boxes for 4x4 trucks that are used off road. I had one myself on one of my square's that was causing problems that I chased for a while and it turned out to be the control box. I go wheeling with my buddies all the time and have seen another msd box with problems as well out on the trail, (two other times) to be exact. I have a buddy that builds baja race rigs and he told me that msd control boxes don't like being beat up off road and don't like taking water bath's all the time either, so that's why I shy away from them.

The square that I removed the msd box from was a 454, 10 to 1 , ported early model closed chamber oval port 396 heads, Comp 270hr roller cam , good old 3310 holley 750 with the msd box and dist. Got it all going and it ran great for a year then I started having problems. So I talked to my machinist who I have used from the beginning of time and he told me to pitch all that race car stuff and go back to an hei . So he built me one for my set up and never a problem since. So since that time , (20 years ago) , I have ran stock and modified hei's in all of my square's. I live at 5,500 feet elevation in the snow country and once you get your ignition and carb. set up right no cold start problem's ever. And going back to an hei with the right curve , total advance , and vacuum canister, there was no difference in performance vs the msd . I am not bashing msd at all I just don't believe all the hype of hot rod ignition systems on an engine that spends most of it's time below 5,500 rpm, so that's my story. If I was building a drag car it would be different.

As for the quick fuel carb. , (as far as looks) , when it came , it would be like ordering a rancho shock vs. a king reservoir shock , absolutely beautiful , I was shocked with the packing and looks of the carb. With that being said looks don't mean a hill of beans so I started adjusting it for first start up while watching t.v. in the living room and what I found was the transition slots were to far open , so I adjusted those down to .020 and the accelerator pump was adjusted to tight so I fixed that and then set the mixture screws to 1 1/2 turns each, so in my opinion you need to check all carbs. out of the box. Holley now own's quick fuel and there quality control is not the best. So I then got my engine up on number one and set the timing , bolted the quick fuel on , filled the fuel bowls and bam , lit right off and ran great.

The slayer series is quick fuels value line carb. so I don't know much about that but if it were me I would step up to the hr or ss series if you were planning to stay with a carb. I went with their off road carb. , (600cfm) because I need it to work at all angle's. So its a very well put together carb. but I just got my k5 home from the exhaust shop and she is a bit rich at 5,500 feet and I have not set up the timing curve's or anything yet, (vortec heads are a different animal) so ignition first then I will go to the carb. So I will report back with results.

Hope this help's.
 

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