I have a '72 Scamp 225 CI with an Offy 4bbl intake. Presently I am running a Holley 390 detuned down as far as it can be. I am getting off line hesitation and another about 30 to 40 mph. I was just at the Cruisin for a Cure car show and one guy stated the Carter carbs work better with the Offy 4 bbl intake. Does anyone know what Carter I am looking for or know where to get one? What are the thoughts on making this carb swap?

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'64 Valiant Conv V8
'72 Scamp /6 4bbl
'79 Adventurer SE

If you are sticking with a four barrel I recommend the Edelbrock 500 CFM performer carb. This is thew same as the old Carter AFB.

I don't agree that one brand of carb works better than another brand on any particular intake. Most any carb should be able to be tuned to run acceptable on any engine, it is a matter of CFM rating and how easy the carb is to tune. Carters are definitely easier to tune than the Holley, but the Holleys can be fine-tuned more than the Carter. Plus Holleys leak more.

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Casually looking for a Clifford hyperpak intake for cheap.

What power valve are you running? What are your vacuum readings? Don't give up on the holley yet, you can get it to work. The carter/eddy carbs are less finicky, while the holley is more adjustable.

Also some more info on your engine would help. Stock comp ratio, stock cam? etc...

1) The pump linkage at the lever needs adjustment to take up the slop at the bolt with the spring. Adjustment is easy pull throttle lever to 100% open and adjust the bolt until it allows a .015 feeler gauge between the bolt head and lever.
2) If that doesn't cure the lean out, you need to change to a better profile pump cam (are you running the orange cam in #1?)
3) What vacc readings do you get during the lean out? Standard power valve for Holley is geared toward a V-8 and typically the street slant six prefers an 8.5 or a 10.5 PV depending on what your build it.

-D.Idiot

Duster, can you explain what "lean out" is? I assume the vac reading is from the vac advance port? I will check on the cam color. Thanks for the help.

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'64 Valiant Conv V8
'72 Scamp /6 4bbl
'79 Adventurer SE

Time to do some homework about carb tuning. Click on the book to order the book you need to purchase, read, and understand.

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Casually looking for a Clifford hyperpak intake for cheap.

No you need to use the direct port under the primary bowl so you see what the carb sees at/under the plates...Lean out is when you don't have enough fuel for the air volume and the engine will suddenly bog or lack power and provide low vacuum reading. This is usually due to an improperly timed pump shot or one that lacks enough fuel to cover the change in throttle plate position when it goes from the idle circuit to the transition and main circuits...also when the load increases (i.e. shifting from 1st to 2nd with highway gearing) can cause a similar condition.

I will highly recommend getting the Dave Emmanuel Holley book over the Vizard book as it is written for a wide range of carbs we use (even the reverse idle screw models) and has detailed pics of where and what all the ports are/do on the carb. Vizard is good and has great books that work on engine theory backed up with decades of Dyno data, but for street use the Emmanuel Book will help with all the nooks and crannies if you aren't familiar with the carb.

-D.Idiot

Listen to DI. He has far more experience with tuning Holley carbs than I ever will, and he can get them to work well, unlike me!

Click this book instead:

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Casually looking for a Clifford hyperpak intake for cheap.

I would bet if we took an afternoon to clean one up and rebuild it and have some time to get hands on tuning, it'd be old hat to you after that.

What do you mean by detuned as far as it can be?


You didn’t say what cam, any head and exhaust modifications that have been made or I hope you have made, as any 4v will be overkill on a stock engine and exhaust system.


If your cam is not too lumpy, out of the box jetting (#51) should be real close, and choice of power valve is dictated by idle vacuum.
Holley tuning videos, and tips here, and here to fill the gap until you get some reading material. And this site may help as well.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I don't know what cam except its not stock. It has a very lopey idle. I have another thread here on /6 going to see if the cam might be a Moon due to info I found on the car. The exhaust has been upgraded to 2-1/4" with stock manifold and FM 40 pipe to the rear bumper.

"Detuning" I am not a carb guy so I am at the mercy of my carb mech. The car had a Holley 650 when I bought it which was way too much. My carb mech tried to make it work and asked me to get the smallest 4 bbl I could which was the Holley 390. He thought it still was too big. (I didn't know the Cubic inch times two rule at that time.) So he then used smaller jets (not sure if they were the smallest made or smallest he had) to get it to run better. I plan to get it back to him today with the new ammo you all have given me. I am glad you guys want to help us "not so informed guys".

I am not sure where the "cam" is I am looking for the color on.

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'64 Valiant Conv V8
'72 Scamp /6 4bbl
'79 Adventurer SE

If you are going to attempt this, you really need to get the Emmanuel book I provided a link to. You say you are not a carb guy but you are trying to jump right in and start tuning a Holley four barrel carb. That is like saying "I'm not a doctor but how do I do open heart surgery?" You need to learn the basics before you go changing things.

Also, the smallest four barrel carb would be the Holley 4360 Economaster 450 CFM carb. It was an economy spread bore carb made in the 70s. Good ones are getting hard to find. You may want to step down to a two barrel carb.

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Casually looking for a Clifford hyperpak intake for cheap.

No, the smallest available is the 390 cfm holley, the 450 cfm 4360 is just that rated at 450 cfm at 1.5" vac. drop just like the 4150 and 4500's...Smaller would be the 350 cfm 2 barrel...but you can get the same results by taking the black secondary spring and installing it in the secondary pod of the 4 barrel holley, that effectively locks out the secondaries on all but the biggest builds, making it function as a small 2 barrel...

The lopey cam is not helping (what is the vacuum reading in gear at idle?), this will take tuning for mileage almost out side the box because the lack of high vacuum at idle assures that the carb will have to be tuned more for the build than for what he wants. If the build is high compression and lumpy I have found that the larger bores in the 450/600 cfm holley tends to allow the throttle plate to stay in a position in idle that covers the transition slots so the idle circuit is really being used 100%, the 390 may need to have plate open a bit more and starts into a whole new obstacle to tuning.

You definately need to get and read the book, taking this ammo to the carb guy will create a conflict between us and him and ultimately put you
in the position where he may stop helping you and you will be on your own.

See if your carb guy can map the carbs parts for us so I can help as time permits:

I would start a Holley 390 on a warmed up slant at:

#51 jets in the Primaries
Plate in the secondaries is stock, but if you use a secondary metering block then #52's should be installed (maybe #53's if needed during passing)
#25 shooter is stock, #28 may be required to mask the bog.
Orange Pump Cam in #1 is OK, #2 position should be tried to see if the
bog gets better...if so the cam needs to be a longer shot so the pink cam in #1 would be in order.
Power valve installed should be an 8.5 or a 10.5 depending on your vacc. reading while passing. If your cam wasn't so lumpy, you might get away with a 5.5/12.5 dual enrichment PV for more mileage improvement, but that is not the case.
Black spring installed in the secondaries until you eliminate the issues above since they are on the primary side...once everything works then move to the Plain Spring for mileage and the purple or long yellow spring at the track if your rear ratio permits it.


More soon,

-D.Idiot

D'OH! I forgot this was a 390 CFM we were talking about. Sorry, my apologies. I will slink away now and be quiet. See what I am saying? I know very little about Holleys. Listen to DI.

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Casually looking for a Clifford hyperpak intake for cheap.