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does anyone run a Percy's adjusta a jet
https://www.slantsix.org/forum/viewtopic.php?t=51907		 Page 1 of 1
Author:  stolan83 [ Tue Apr 30, 2013 10:16 am ]
Post subject:  does anyone run a Percy's adjusta a jet
I have read a bunch of posts on how big of a pain it is to make the holley 390 right and was thinking about using a adjust a jet from percys to make things a little easyer on my self, any suggestions
Author:  Rick Covalt [ Tue Apr 30, 2013 10:47 am ]
Post subject: 
Quote:
make things a little easyer on my self, any suggestions
Install an Edelbrock 500. :lol: :lol: :lol:

Rick
Author:  Reed [ Tue Apr 30, 2013 11:15 am ]
Post subject: 
Quote:
Quote:
make things a little easyer on my self, any suggestions
Install an Edelbrock 500. :lol: :lol: :lol:

Rick
+1. Holleys are for guys who really like to fine tune every last operation of their carb. For everyone else or for daily drivers, get an Edelbrock Performer/Carter AFB in the 500 CFM variety or go with a two barrel carb.
Author:  Ssg Pohlman [ Tue Apr 30, 2013 11:55 am ]
Post subject: 
Don't know yet but I can say that I ordered one to go w a holley 2bbl. I'll do a full write up on it when I get home in a cpl months. So if you're not in a hurry I'll post up my findings.
Author:  stolan83 [ Tue Apr 30, 2013 12:59 pm ]
Post subject: 
well I guess that I will get one a let you know how it goes too. Any other suggestions on tuning my holley would be great
Author:  Reed [ Tue Apr 30, 2013 1:06 pm ]
Post subject: 
"Easy to tune" and "Holley" don't go together. Yes, Holleys can be tuned just fine, but I don't think that doing so falls into the category of things that are easy to do.

If you want easy to tune, run a Carter/Edelbrock.
Author:  DusterIdiot [ Tue Apr 30, 2013 6:35 pm ]
Post subject:  Yep...
Quote:
thinking about using a adjust a jet from percys
I don't run these as my generation was plagued by the bad quality of the first adjustable jet kits where they either dialed wrong or out of 'range', or in some really bad cases they fell out of the metering block after wiggling loose and caused some issues.

I know at least one racer now that uses this system and it sure does make 'jet changes' a quick affair.

Once you are familiar with the Holley system it isn't bad, but it is all about tuneability (and unlike Carter, the Holley does have "modularity"- i.e. within the standard family you can swap blocks, jets, pods, cam, springs, even you can swap base plates and throttle bodies if needed a specific midrange CFM). I won't knock the carter/Ede for certain reasons, but after tuning a hyperpak for street the holley is the only one that allowed full unsquare jetting, throttle body modifications, and tuning that would not be fully possible with the AFB.

I'm going to give Reed some crap here, since he sold me a very nice list-7508 2 barrel 2300, after going through it with a rebuild kit (took 10 minutes to clean and reassemble adjust the parameters), it went on a 1979 225 with a super six manifold and Mr.Gasket 1937. Should have it running under the hood of the FDX by Monday. There are less parts in it than a BBD...and unlike the BBD, all the parts that needed replacing I culled from a $30 junkyard 650 cfm 4150... (saving about $40 in new parts). :wink:

Any carburator is easy to tune with these 3 items:

1) A good Tech Manual (Get Dave Emmanuel's Holley book, the pictures help see what and why).
2) Vacuum Gauge hooked up while super tuning.
3) Oxygen Sensor and Gauge - these will help keep the carb in the goal posts while you make changes and daily drive it (this also saves time over pulling spark plugs- but should not completely replace this practice to ensure that the readings are on par with what is happening in your combustion chamber).

-D.Idiot

"When talking good air fuel calibration you should never settle for 'that's good enough'...leaving 1 mpg on the table from lazy tuning on a car that gets about 20 mpg is like leaving 5% of the cost of a gallon of gas for the gas company to take to the bank...$75-120 a year may not seem like much, but that's money that could be going toward improving your ride or going out more often..." (Automotive Tech instructor at local college- I'm not going to name him, but he is right...and he was not talking about a chevy).
Author:  Reed [ Tue Apr 30, 2013 6:44 pm ]
Post subject: 
What can I say? DusterIdiot is better at tuning carbs than I am. Or maybe I am just lazy. :wink: :lol: I have just always had better luck tuning Edelbrocks/Carters than Holleys, but, then again, I have never run any vehicle as modified as what DI runs.
Author:  Sprag [ Tue Apr 30, 2013 7:19 pm ]
Post subject: 
I have yet to try any of the adjust-a-jet thingies but I'd like to, so I'd be interested in hearing about them as well. I was scared away by the aura of bad ju-ju that seemed to hover over the early designs as D. Idiot mentioned above but I am otherwise a big fan of the square flange Holley carbs. I think they are the easiest to tune when you have ventured well beyond the out-of-box range but I think that requires one more thing tacked onto D.I's list;

4) A vast array of tuning goodies - jets, pump nozzles and cams, gaskets, hardware, springs etc

This gets expensive quick though, but it's a godsend to have these on hand at the shop or track. For me it makes it much easier by tuning separate things in smaller increments and perhaps more importantly, it keeps me 'in the groove' during a carb thrash because there are less distractions and less time for second guessing everything. Did I mention I really love Holley's? :D
Author:  Matt Cramer [ Wed May 01, 2013 7:50 am ]
Post subject: 
I tried one on a blow through carb setup. Easy enough to set up and use, but I couldn't get the carb in tune - it had problems WAY beyond a the jetting being off.
Author:  DusterIdiot [ Wed May 01, 2013 8:17 am ]
Post subject:  Wold like to know...
Quote:
Easy enough to set up and use, but I couldn't get the carb in tune - it had problems WAY beyond a the jetting being off.
Just for my reference, what model # and list number was the carb?
Was it new or did you get a junkyard special?
What mods were made to the carb (I know that there are a heavy list of mods for blow through apps depending on blow through throttle bores only, or pressurize entire carb.)

I know that quality control on the Avengers and Demons had been lacking, but just curious if yours was a similar generation.

Thanks,

-D.Idiot
Author:  stolan83 [ Wed May 01, 2013 11:02 pm ]
Post subject: 
So really what I should do is spend is spend the money on a Air to fuel guage in stead of the adjust a jet. I know that there some really in depth posts on tunning the 390 and as it sits the one I own is how you would get it out of the box. As a starting point, I know that I need to change the PV and am going to install the quick change secondary and get the spring set package that summit has. Where should I start and what aray of jet sizes should I get. What would be the ideal book or manual for the holley 390 :?:
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