Re: Holly mechanical or vacuum secondary
[Re: 73bbroadrunner]
#1403314
03/16/13 07:44 PM
03/16/13 07:44 PM
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Joined: Jan 2003
Posts: 9,826 las vegas
70AARcuda
master
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master
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las vegas
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holley 3310 vac sec 750 cfm
Tony
70 AARCuda Vitamin C 71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield) 71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas) 71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)
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Re: Holly mechanical or vacuum secondary
[Re: 73bbroadrunner]
#1403316
03/16/13 07:48 PM
03/16/13 07:48 PM
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Joined: Jan 2003
Posts: 1,255 Columbus, GA
Michael Ecks
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600 sounds way small for 400ci. My 360 has a 670 Street Avenger and seems like it wants more, so I am going to try a 770 vacuum soon. It is harder to go too big with a vacuum since it will only take as much as the engine can handle when properly tuned (very gross simplification). Some 318's came with thermoquads capable of 750ish cfm, but the vacuum operated air valve made it possible, unlike say a mechanical double pumper.
I'm sure others will chime in, and probably all ask the same question...What is your intended usage? Driver, dragstrip, or street/strip.
"The happiness of your life depends upon the quality of your thoughts" ~ Roman Emperor Marcus Aurelius
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Re: Holly mechanical or vacuum secondary
[Re: 5spdcuda]
#1403321
03/16/13 09:18 PM
03/16/13 09:18 PM
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Joined: Jan 2003
Posts: 1,255 Columbus, GA
Michael Ecks
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Quote:
That makes three of us. Hard to beat the 3310 for general street/strip use, especially if you equip it with a quick change spring kit,electric choke, and secondary metering block.
If we are talking a new carb, doesn't the quick change spring kit, choke, and secondary metering block pretty much equal a holley street avenger or quick fuel slayer? Or am I missing something?
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Re: Holly mechanical or vacuum secondary
[Re: Michael Ecks]
#1403322
03/16/13 10:56 PM
03/16/13 10:56 PM
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Joined: Jan 2003
Posts: 12,301 Benton, IL.
DaveRS23
Special needs idiot
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Special needs idiot
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Yep, 3310. Cheap and rocks with just a few easy mods.
Master, again and still
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Re: Holly mechanical or vacuum secondary
[Re: Michael Ecks]
#1403323
03/16/13 11:19 PM
03/16/13 11:19 PM
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Joined: Jan 2003
Posts: 5,444 Indiana
YO7_A66
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master
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Indiana
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""If we are talking a new carb, doesn't the quick change spring kit, choke, and secondary metering block pretty much equal a holley street avenger or quick fuel slayer?
The QF Slayer also has:
""the Slayer™ provides all of the popular options: changeable idle air and high-speed air bleeds, 3-stage emulsion circuits, changeable primary idle feed restrictions and power valve restrictions. A real welcomed feature is the QFT QuickSet adjustment on the vacuum secondary diaphragm that provides a quick external twist adjustment without changing springs. Secondary metering can be altered with changeable main jets and the secondary float is also notched for jet extensions.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Holly mechanical or vacuum secondary
[Re: YO7_A66]
#1403324
03/17/13 11:35 AM
03/17/13 11:35 AM
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Joined: Jan 2003
Posts: 12,301 Benton, IL.
DaveRS23
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Two thoughts here. First, there are not likely to be many Slayers or the like at swap meets for $75-$100 like the 3310s.
Second, if the OP needs help sizing the carb, he is not likely going to be able to take advantage of the added tuneability of the more expensive carbs.
Besides, if he does start learning to tune, he would be better off experimenting with a $75 carb than a $300 carb.
Master, again and still
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Re: Holly mechanical or vacuum secondary
[Re: DaveRS23]
#1403327
03/17/13 06:36 PM
03/17/13 06:36 PM
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Joined: Jan 2003
Posts: 1,255 Columbus, GA
Michael Ecks
pro stock
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pro stock
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Quote:
Two thoughts here. First, there are not likely to be many Slayers or the like at swap meets for $75-$100 like the 3310s.
Second, if the OP needs help sizing the carb, he is not likely going to be able to take advantage of the added tuneability of the more expensive carbs.
Besides, if he does start learning to tune, he would be better off experimenting with a $75 carb than a $300 carb.
I'll see your two thoughts and raise you two more.
1. A $75 swap meet carb, is most likely going to need a carb kit and someone knowledgeable to clean the carb and install it. I don't know what a local shop or shadetree guy might charge for a low buck rebuild, but a restorer would be asking what $600?
2. A swap meet carb isn't likely to be a specific one for a 400 mopar, much less the OP's particular mods to the engine. Which means it will need to be tuned anyway as far as checking/changing jets and on car adjustments.
FWIW It had been a long time since I tuned a holley when I put the Street Avenger on my 360. It ran decent right out of the box, following the printed instructions got me a good idle, and performance as good as Tquad I had restored, and the jets that came in it seem pretty close to where they need to be based on reading the plugs.
No warring going on here just bench racing, but they are some extra things for the OP to think about. If you are not very experienced with carbs and do want to learn to rebuild one yourself, in that case I would instead recommend picking up a used Carter AFB/AVS (Edelbrock). Both are vacuum secondary, the AFB uses a counterweight and is not meant to be adjustable, the AVS style uses a spring and is very easy to adjust. Both have a one piece bowl less prone to leak, fewer gaskets, fuel metering can be adjusted without taking the carb back apart, less sensitive to warpage (I'm looking at you-holley metering plates), easier to work on all around IMHO.
Last edited by Michael Ecks; 03/17/13 06:47 PM.
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Re: Holly mechanical or vacuum secondary
[Re: Michael Ecks]
#1403328
03/17/13 08:27 PM
03/17/13 08:27 PM
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Joined: Jan 2003
Posts: 12,301 Benton, IL.
DaveRS23
Special needs idiot
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Special needs idiot
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Two last points, maybe.
$600 for a rebuild?!?!?!?!??!?!?!?!?! Again, if the Op cannot clean up a carb and throw gaskets in it, he won't be able to tune it.
And the CarterBrocks have mechanical secondaries. Even the secondary air doors are air flow opened, not vacuum.
Master, again and still
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Re: Holly mechanical or vacuum secondary
[Re: DaveRS23]
#1403330
03/17/13 11:12 PM
03/17/13 11:12 PM
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Joined: Jan 2003
Posts: 1,255 Columbus, GA
Michael Ecks
pro stock
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pro stock
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Quote:
Two last points, maybe.
Touche'my friend!
I said $600 for a "restore" back to factory original condition and finish. One of the restorers here on the board charges $400 for 4 barrels, my guy quotes $395-420 assuming it needs no new hard parts. Okay I was off, been a while since I priced. As I said, I don't know what a regular shop charges for a more typical "rebuild" since I've always done my own since learning from my friend who does restorations.
Vacuum versus flow operated... I admit defeat. Can we agree both make it harder to over-carb than using a double pumper, which is what always come into my mind when someone says mechanical secondary?
I still say if the OP wants to rebuild his own an AFB/AVS is easier to learn on for a first carb.
@5spdcuda
Quote:
Total price for everything $391.96. Price for a Quick Fuel 750 vac. sec.=$526.99, $135.00 more than the 3310 with the options I recommended.
Not sure which quickfuel carb you were looking at, here is the one I was thinking of Summit - Quickfuel 750
It has a screw adjustable secondary opening instead of changeable springs and includes the electric choke. I'm not familiar with the secondary setup, I'm guessing the screw adjusts a restriction in the air passage to the diaphragm? It does lack the secondary metering block, but has a metering plate designed for changeable jets. $299.95. I'm like you though and prefer the block, which is while I'll stick with Street Avengers for now.
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Re: Holly mechanical or vacuum secondary
[Re: Michael Ecks]
#1403331
03/18/13 09:56 AM
03/18/13 09:56 AM
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Joined: Jan 2003
Posts: 12,301 Benton, IL.
DaveRS23
Special needs idiot
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Special needs idiot
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No more points, but a few thoughts and a couple more questions. The OP probably should note that ALMOST everyone in this thread had recommended the 3310. I am a little lost on the concept of restoring a carb in this thread. The OP wants a recommendation on a style and size of carb. I didn't see any reference to "correct" or OE looking in his question. And why would anyone spend the coin on a used carb, that then needs more money spent on it than a new one would cost? You should be able to get most 4150 style carb cleaned and gasketed for $100 or so including gaskets. If it needs more than that spent on it, it would probably have been a bad choice to begin with. For most of us, an electric choke is more trouble than it's worth. Which is why most of these type of carbs are still offered without them. I'll say again, the CarterBrock style of carbs are MECHANICAL secondaries. Just like a Double Pumper Holley. The difference between those is the type of secondary actuation enrichment. Holley uses accelerator pumps, while the CarterBrocks use the air valve to pull extra fuel from the boosters. I guess the CarterBrocks are easier to get apart. But when it comes to tuning, have you seen the rod/jet chart in the tuning manual? What a nightmare, and I would like to see someone try to tune one without the chart. For this application, I do not see the value of the secondary metering block. The primary is where most if not all the street tuning happens. You basically tune the WOT mix with the secondaries and that is usually pretty close to begin with. I rarely need to change much if anything on the secondaries, if the idle mix isn't too far off. And then I can get it close with the primaries anyway. I do a agree that the Double Pumper would be a poor choice here. But not necessarily because it has mechanical secondaries. But because it is metered for the track, which is way too rich for this kind of street application.
Master, again and still
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Re: Holly mechanical or vacuum secondary
[Re: DaveRS23]
#1403332
03/18/13 10:21 AM
03/18/13 10:21 AM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Here's another vote for the 3310 Holley, forget the choke, get a secondary spring assortment, if you buy used make sure the throttle plate isn't warped, and don't overtighten when you bolt it to the intake manifold (100 inch pounds is correct) unless you want a warped/broken throttle plate and a huge vacuum leak.
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