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AVS or Holley #2656307
05/17/19 04:15 PM
05/17/19 04:15 PM
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl Offline OP
pro stock
Scott Carl  Offline OP
pro stock

Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
74 Challenger, 318 with mild cam (Comp listed as stock 340/360 cam) AVS. This was a salvaged carb from a 71 LP 383 #MO 4966S. 600 cfm(?) I put a kit in it and it seems to run ok, but recently, I was recommended to check the floats as it was having h
warmed up idle issues and WOT loss of power (crapped out like it was fuel starved. I re-dicovered that the floats are not the same. I could only get the float level at the very end on one as it slanted up toward the needle valve seat. Other was level when adjusted to height. Drop level seem similar on both. Still has issues when warmed up but acceleration and WOT better, but not great.

OK, the question. Keep working with the AVS, or get a Holley? Seeing them on Ebag for $50 to $80. then the price of a rebuild kit. Opinions?

Thanks, Scott

Re: AVS or Holley [Re: Scott Carl] #2656343
05/17/19 05:26 PM
05/17/19 05:26 PM
Joined: May 2019
Posts: 6,176
nowhere
S
Sniper Offline
master
Sniper  Offline
master
S

Joined: May 2019
Posts: 6,176
nowhere
Originally Posted by Scott Carl
74 Challenger, 318 with mild cam (Comp listed as stock 340/360 cam) AVS. This was a salvaged carb from a 71 LP 383 #MO 4966S. 600 cfm(?) I put a kit in it and it seems to run ok, but recently, I was recommended to check the floats as it was having h
warmed up idle issues and WOT loss of power (crapped out like it was fuel starved. I re-discovered that the floats are not the same. I could only get the float level at the very end on one as it slanted up toward the needle valve seat. Other was level when adjusted to height. Drop level seem similar on both. Still has issues when warmed up but acceleration and WOT better, but not great.

OK, the question. Keep working with the AVS, or get a Holley? Seeing them on Ebag for $50 to $80. then the price of a rebuild kit. Opinions?

Thanks, Scott


The AVS is a pretty basic 4bbl, not too much you can fool with and not too much you can take apart.

The Holley can be taken much further apart and you can adjust many more things. IOW you can get into more trouble with it if you are new to carbs.

That said, I can't imagine that if an AVS is giving you fits that a used Holley of unknown condition and in need of rebuilding would be a good solution.

You do know that you can bend the tang on the AVS float to "level" it out?


Re: AVS or Holley [Re: Sniper] #2656351
05/17/19 05:59 PM
05/17/19 05:59 PM
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl Offline OP
pro stock
Scott Carl  Offline OP
pro stock

Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Yeah, I messed with the odd float a little but I want to put a new plunger in so I'll probably spend some more time on the floats, then. As for the Holley, I'm probably still considered a novice on carbs; Rebuilt a a couple carter 2bbl and one Stromberg as well as the carbs on two different Honda MCs One a 750 with four carbs. Now that was a challenge. But I'm a piddler. I like to fiddle with stuff. Really considering getting a Holley just for the experience. I could always sell it for cost after I put the kit in if I decide not to use it. work

Re: AVS or Holley [Re: Scott Carl] #2656388
05/17/19 09:00 PM
05/17/19 09:00 PM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert Offline
Circle Track
Happy Birthday RapidRobert  Offline
Circle Track

Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
stay on the AVS & work with the float arm till you get it level/correct setting & then see how it performs. All OE AVS's are lean from the discombobulated gov't emission regs of the time & can benefit from converting to the eddy performer 2 step rods/short pri jets in one of their strip kits that is close to but slightly richer on the rods/jets than what is in the AVS now or swap AVS stuff if you have extras. If you ever get to Lincoln I would love to take a look at it. EDIT what Sniper said just bend the "connector tang" in the middle till the float is level (I'm assuming "level" is the float setting). Dont put any pressure on the needle/seat in this process. let the float rest lightly on it after each adjustment till you get it where you want it.

Last edited by RapidRobert; 05/17/19 09:11 PM.

live every 24 hour block of time like it's your last day on earth
Re: AVS or Holley [Re: Scott Carl] #2656396
05/17/19 09:37 PM
05/17/19 09:37 PM
Joined: Jan 2003
Posts: 1,979
s. e. pa.
C
calrobb2000 Offline
top fuel
calrobb2000  Offline
top fuel
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Joined: Jan 2003
Posts: 1,979
s. e. pa.
hi

holley ,holley ,holley ,holley !

my son has a 66 valiant 318 that he built < his first > runs consistant 13.5 1/4 mile with a 750 holley !

Last edited by calrobb2000; 05/17/19 09:38 PM.
Re: AVS or Holley [Re: calrobb2000] #2656414
05/17/19 10:28 PM
05/17/19 10:28 PM
Joined: Feb 2004
Posts: 855
ontario canada kingston
aspenrt360 Offline
super stock
aspenrt360  Offline
super stock

Joined: Feb 2004
Posts: 855
ontario canada kingston
I have run most types of carb, they are all pretty good if you take the time to sort them out. generally speaking i tend to find carter and the newer edelbrock copies a bit easier on fuel and good running but i find holley carbs are more forgiving and a touch harder on fuel. if i am looking for pure performance a double pumper is the way to go but in general i tend to end up with vacum secondary holleys on my cars i find them a easy to tune as i have the jets and small bits to do them the eddys tune ok but you will need to get the tuning kit for the jets and metering rods and springs. also with a modest cam an eddy or carter is just fine run a big cam and holleys are less of a hassle to get tuned in right. if i was you i would look for the newest carb you can find to rebuild or better yet one that already runs good so all you have to do is tune it. if you get a holley try to find one that is new enough to have blue non stick gaskets and blowout protection.


2013 Chrysler 300 touring 1974 Dodge Charger SE. 360-727-8.75-3.23 sure grip 1972 Dodge Dart Swinger 1995 Dodge Ram 1500 4x4
Re: AVS or Holley [Re: Scott Carl] #2656505
05/18/19 09:39 AM
05/18/19 09:39 AM
Joined: Jan 2003
Posts: 11,895
Benton, IL.
D
DaveRS23 Offline
Special needs idiot
DaveRS23  Offline
Special needs idiot
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Joined: Jan 2003
Posts: 11,895
Benton, IL.
For a mild small block street engine, there really is no clearly superior carb. Both have their particular issues and both can be made to work well and in the end, if properly tuned, will perform equally. The biggest difference when starting to tune the two is flexibility and parts availability. The Carters are not real easy to tune particularly in the low speed transitions. And parts can be a problem to find without ordering and waiting. The Holley platform is easier to access the points that usually need to be addressed when tuning and parts are everywhere. Heck even my local Oreilly's has Holley parts on display.

It is really important to start with a carb that has as close a tune as your engine needs to start with. The farther the original tune is away, the more fiddling and more tools and knowledge will be required to get it right. But choosing which one that is, is a real challenge. And remember, 40 year old carbs were designed to deliver a very different fuel than they will see today, so even a carb that was designed and tuned for a particular engine in the 60s or 70s, will need some adjustments to run properly today.

If someone wants to tinker with carbs, whether it is a Carter or a Holley, there are certain bare essentials required. First are books. Because a good understanding of the circuits and location of metering orifices is an absolute must. And a good selection of tiny drill bits because may orifices in both brands are drilled, not screwed in. Or you can get a hand full of bleeds and a drill bit and tap to install screw in bleeds when space allows. And at least a narrow band O2. A wide band is much, much better, but a narrow can suffice for beginning tuning. The only advantage to the narrow band is that it is much cheaper. And don't forget time. It will take a lot of time to read and understand the workings of your chosen platform. And then more time tuning and driving and tuning and driving. But all of that is part of the attraction for guys that mess with carbs. While all of that is why most guys don't mess with carbs.

Here is an alternative to forego all of that if learning to tune their carb is not on someone's life list. The Street Demon. This is the best carb I have ever installed on mild street engines.

https://www.youtube.com/watch?v=DPOuEOkazVc

https://www.hotrod.com/articles/ccrp-1209-01-street-demon-carburetor-the-new-625-cfm/

https://www.ebay.com/itm/Factory-Refurbished-Street-Demon-1901-625CFM-4bbl-Carb-/351711332709

https://www.youtube.com/watch?v=YNAlVFtUFL4


Master, again and still






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