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Old 08-11-2010, 01:27 PM   #26
dbmx66
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Re: which carburetor!

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You can remove the choke stuff. Its done all the time. Just be careful and make sure you dont end up with metal shavings in bad places. I would take the entire carb apart before cutting anything. The less places there are for a piece of metal to get trapped the better off you are..
thank you
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Old 08-11-2010, 01:46 PM   #27
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Re: which carburetor!

I had to go back and re-read the posts to make sure and try to get a feel for what the "truck" is going to be used for. You say you want to turn it into a real beast down the road. That term is in the eye of the beholder. You go big enough and the 750 might not be enough.

If it was me......I would start off by running the darn thing the way it came from Holley. Don't go milling anything just yet. The gains are there but small. the air intake factor can come in a bit too. Before I was running the dual 4 setup, I had the K&N air cleaner with the mesh top. Makes it breathe a lot better. In that case, the milling will be even less because you are able to pull air in directly from above in stead of from the sides from a cleaner with a steel top. Just remember we are talking small things here and most of them really won't even be detected in the "seat of your pants dyno".

These Holleys are fairly close from the factory and are jetted a tad rich and for sea level. Put the darn thing on outta the box and read your plugs for both the primary and secondary circuts, then go from there. You might just love it as is.

The car you see below was a car i built back in '89 when I was just a lad. I had the paint shop put on a bunch of extra clear because I wanted to wet sand the daylights out of it. There was actually a couple of spots where I had some clear runs on the spoilers (which I took care of). Bottom line is the car looked so fantastic I was afraid to wet sand it and just left it alone. Moral of story is sometimes well enough is better left alone!!!
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Old 08-11-2010, 02:08 PM   #28
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Re: which carburetor!

i have a velocity stack, that will stick out of the hood, an according to the people i talked to the ran them sed they gain a fair amount of power becuase of the big increase of airflow.
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Old 08-11-2010, 02:17 PM   #29
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Re: which carburetor!

.....and it's downward air flow. Do what you want but I wouldn't get excited about milling the choke right off the bat.
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Old 08-11-2010, 03:33 PM   #30
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Re: which carburetor!

is down ward airflow good?
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Old 08-11-2010, 04:12 PM   #31
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Re: which carburetor!

It's all really downward. lol

Does the air cleaner with the metal top VS the mesh top make sense?

We're still talking small stuff again. Barely noticable. The only time you can really make a big diff is with a scoop or a hood snorkle feeding to an aluminum pan that seals the carbs to the hood so the air has to go in. That's racing stuff though.

For the sake of not getting off track.....get that Ultra Pumper and go!
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Old 08-11-2010, 04:12 PM   #32
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Re: which carburetor!

I forgot about Pro Systems. You can go on Ebay and buy you an old 750DP for $100 or less then send it to Patrick at PS along with about $350(+/-) and he'll do whatever needs to be done to make that carb work for YOUR setup. That's about what he quoted me last year, but I decided to learn to tune my carb myself.
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Old 08-11-2010, 10:26 PM   #33
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Re: which carburetor!

well she came today, and some other goodies! =]

march performance alternator bracket kit was back ordered tho
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Old 08-11-2010, 11:57 PM   #34
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Re: which carburetor!

That carb should have come with a Holley DVD. I suggest you watch it. I was surprised that it wasn't real cheesey. It's acutally a very good tuning disc. It will go into just about every aspect of metering fuel in the carb including reading plugs. I would certainly not mess with it initially. Bolt it right on and follow the instructions. Let us know how it goes.

P.S. Looks like they even pre-bent the slip rod so the butterflies will actually be straight up and down at full throttle.

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Old 08-12-2010, 12:29 AM   #35
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Re: which carburetor!

ill def let you know. and if i have any questions you'll be the one ill ask.
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Old 11-18-2010, 12:07 PM   #36
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Re: which carburetor!

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Say no to the AFB clone. No adjustment for secondary airflap opening rate is a huge detractor.
The Edelbrock 650 AVS has secondary adjustment btw.
I use a Holley 750 DP on my 406 in Camaro but I still like the 650 AVS in my 350 truck.
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Old 11-18-2010, 05:07 PM   #37
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Re: which carburetor!

dbmx do you have a build thread on your truck?
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Old 11-18-2010, 06:35 PM   #38
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Re: which carburetor!

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dbmx do you have a build thread on your truck?
nope. never made one, i think i should have, cause stuff gets changed every week.
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Old 11-18-2010, 06:37 PM   #39
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Re: which carburetor!

Yea make one and let me know so I can suscribe
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Old 11-18-2010, 06:45 PM   #40
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Re: which carburetor!

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Yea make one and let me know so I can suscribe
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ill let you know wen i do bud.

kinda random, but how old are you again?
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Old 11-18-2010, 07:06 PM   #41
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Re: which carburetor!

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ill let you know wen i do bud.

kinda random, but how old are you again?
19 wbu
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Old 11-18-2010, 07:12 PM   #42
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Re: which carburetor!

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19 wbu
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its good to see im not only young person on here. ill be 18 january 8th
ive got 2 jobs so i can pay for this money pit of a vehicle. hahaha

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Old 11-18-2010, 08:26 PM   #43
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Re: which carburetor!

Hhaha yea I know. Full time job and college full time. And a gf haha no time or money
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Old 11-19-2010, 01:30 AM   #44
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Re: which carburetor!

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Hhaha yea I know. Full time job and college full time. And a gf haha no time or money
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lol i know what you mean.
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Old 11-19-2010, 03:15 PM   #45
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Re: which carburetor!

i got a 950 hp on my 406. it probably only flows 830 or so but my 406 likes it
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Old 11-19-2010, 03:27 PM   #46
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Re: which carburetor!

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i got a 950 hp on my 406. it probably only flows 830 or so but my 406 likes it
I've got a 750 on my 400. It seems to much. It's running rich on idle. Might have to jet it down
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Old 11-19-2010, 04:36 PM   #47
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Re: which carburetor!

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I've got a 750 on my 400. It seems to much. It's running rich on idle. Might have to jet it down
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Assuming you are talking about a 750 Holley, you can't jet it down for idle quality. The idle feed restrictors are fixed. Jetting is a main circuit item. It won't help you at idle. You can try looking at your throttle blade position on the transfer slot to make sure it's not too exposed (usually will cause a high idle but not always if your timing is really retarded). Your trans slot should be exposed as deep as it is wide (.020). You can also try to re-adjust the sir/fuel needles. Lastly, but not likely, is you can check to see if your power valve either slightly torn, or the wrong number and it's not even closing. These would both produce a VERY rich mixture and should idle really rough or not want to idle at all due to loading up.

KQQL IT....your 406 likes that carb because it is, in fact, just over 800 cfms and has a small venturi the size of a 750 (1 3/8th)....usually producing a nice, snappy throttle.

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Old 11-19-2010, 04:56 PM   #48
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Re: which carburetor!

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Assuming you are talking about a 750 Holley, you can't jet it down for idle quality. The idle feed restrictors are fixed. Jetting is a main circuit item. It won't help you at idle. You can try looking at your throttle blade position on the transfer slot to make sure it's not too exposed (usually will cause a high idle but not always if your timing is really retarded). Your trans slot should be exposed as deep as it is wide (.020). You can also try to re-adjust the sir/fuel needles. Lastly, but not likely, is you can check to see if your power valve either slightly torn, or the wrong number and it's not even closing. These would both produce a VERY rich mixture and should idle really rough or not want to idle at all due to loading up.
http://www.summitracing.com/parts/HLY-0-80508S/
ive got that carb. yes a holley. its bran new.

but still realy rich at idle. i turned the idle fuel mix. (2 screws on the front half of the carb on each side) and still realy rich. maybe my timing is messing with it? just dont seem right. it could be rich all the way around too. i just cant tell at WOT. if de jeting it. would that lean it out more
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Old 11-19-2010, 06:32 PM   #49
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Re: which carburetor!

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i got a 950 hp on my 406. it probably only flows 830 or so but my 406 likes it
I'm glad your 950 works well. I ran mine for most of the summer then put the 850 back on.

I tried every thing that I could to tune out a blubbery spot in the lower RPM range 2200-3000 witch I cruse around town at. The only thing I haven't tried is to slow down the low speed air bleeds. I'm not that brave to take a drill to it.
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Old 11-19-2010, 07:09 PM   #50
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Re: which carburetor!

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I'm glad your 950 works well. I ran mine for most of the summer then put the 850 back on.

I tried every thing that I could to tune out a blubbery spot in the lower RPM range 2200-3000 witch I cruse around town at. The only thing I haven't tried is to slow down the low speed air bleeds. I'm not that brave to take a drill to it.
Its got a weird roll in issue, if i snap it down its good. I cant explain it well an ez roll into it it has a flat feel
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