is a 500 cfm 4bbl carb too much...?
Read about a 225 hp build. was thinking I might go this size over a 350 holley.

any ideas...? Don't care about fuel economy. just want some power.

when I do this will have had 1.7 1.44 valve job, compression around 10:1. and a port polish job with extractors coil and ignition.

Sound good...? Next thing is that I will get a different cam not sure on the specs etc.

is this a bad idea...? I've been told a 4bbl and a 2bbl cfm is measures differently and isn't exactly comparable...?

An engine is an air pump. The faster it will turn up, the more air it can move in theroy. If you have a stock grind cam, air pumping will be limited due to not enough overlap, and limited rpms. The hotter the cam, the faster the engine can turn up, to a point that is.

A small Holley 390 CFM carburetor matches closely to a moderately modified engine with high compression, oversized valves, headers, and what we used to call a race cam as to the amount of cfm it cam pump. This set-up also yields a low vacuum signal.

Stepping up to a 500 cfm carburetor may or may not improve performance. What it could do is introduce bog, & poor fuel economy due to a poor vacuum signal, and the engine not being able to attain high enough air movement to take advantage of the extra capacity provided by that larger carburetor.

Some of the racers use 500 & 600 cfm carburetors, but those cars aren’t generally street driven.

You will need to match the carburetion to the engine build. Holley has a Carburetor-to engine build [url=http://www.holley.com/applications/CarburetorSelector/CarbSelection.asp] calculator[/url]. Josh Skinner has a Carburetor [url=http://slantsix.org/articles/Josh_Carb_Article.htm] Article[/url] discussing engine build & carburetor choice that is informative. There are several different builds listed on this site that you should consider a well.

Yes, two barrel carburetors are rated under a higher vacuum, than four barrel carburetors. I’m trusting the dome here, 2v are tested at @ 3â€￾Hg., and 4v @ 1.5â€￾Hg. Josh’s article addresses this in section 3.

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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

No, not if its the new Edelbrock AVS or the 1403.
Once you increase compression and go to the bigger valves and cam it will want to breath. There is a post a few weeks back that has a carb article showing how much the 500 primaries are rated at for flow. It's about the same as a Carter BBD around 200 CFM. It's worth reading.......and puts all the carb options in context. Several of the guys on this site are running the Edelbrock and are happy with the results. Install it and go....the Holley 390 takes a lot of tuning......

http://www.rasoenterprises.com/index.ph ... &Itemid=49

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

I am running the 500avs and find it to be a very good carburetor. I would recommend it to anybody.

But it wasn't bolt on and run affair and my engine is not stock by any means.

To get it to run right I had to adjust the floats which were off from the factory, replace the inlet needles and jets which leaked from the factory. Once that was done, I then jetted the primaries up about 3 steps, the secondaries by one step and change the step up springs to the "orange" ones.

That still was probably cheaper than the following Holley mods to an "8007":

Add Secondary metering block and #52 jets in secondary spots (maybe #53 if need richer)...
Add adjustable secondary vacc. pod, (for quick changes from stiff mileage spring to "purple/long yellow" drag configuration).
Buy secondary spring kit. (purple/yellow)
Buy acc. pump cam kit to dial in proper acc. pump shot. (is it Orange 466 or Pink 330?)
Buy Acc pump shooter of appropriate size (#28 or #32?)
Regasket Kit after tearing apart...

-D.Idiot

We have bolted on 2 Edelbrock carbs on engines and they ran well right out of the box. A 600 on Ryan's modified engine and a 500 his bone stock 85 pickup. Of course we did make some adjustments down the road but they are easy to make. Just my 2 cents

Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Like some of the guys above, I ran a 500 Eddy (still do) and it works real good. My new 390 Holley was good for only a year and then started to act up with too many problems so I went with the 500. The engine was stock with just a intake, headers, and a 2 1/2 single exhaust. 2 cents too !

Another vote for an Edelbrock carb. My old 84 Ford van was factory built with a Holley 4160 carb. I messed with that carb for years and it never worked right. Always had leaks, flat spots, bogs, etc... I finally got fed up and bought a new Edelbrock 650 CFM carb. Bolted it on and it worked perfectly.

Holleys are good if you like to tinker (and know how) but Edelbrocks are good if you want to just put the carb on and drive.

I think on a slant the AVS would be better than the performer/AFB since you could fine-tune the secondaries.

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Casually looking for a Clifford hyperpak intake for cheap.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

I'd like to throw my 2c in also. For ease of tune-ability I'd stick with your original plan Brussel and go with a 2 BBL 350 Holley. You might need to change jets and power valve to suit your engine but that should be it. I've just recently removed a 390 Holley after running it for 2.5 years and gone back to a 350. And to be quite honest, the 390 didn't give me that much more HP than the 350.
As mentioned before, if you love to tinker you'll love a 4BBL Holley. I don't think a month went by without me trying a different combo of jets/spring/shooters/PV etc to chase that sweet spot. I did eventually get the 390 tuned well, but for the ease of bolt and go hassle free motoring I vote for a 2BBL Holley.
The 350 Holley is enough for my engine, it still revs out to 5500 rpm and runs the 1/4 mile in the mid 15's, that's good enough for me.

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62 Valiant, 225cid Slant 6/PB 904 with lots of good bits

http://www.moparmarket.com/readersrides ... user=SV162

...and when you get tired of re-jetting your Holley for the seasons, and/or every 1000 ft track elevation change, bolt the Eddy 500 AVS or AFB on there, and never mess with it again.
Anybody mention -No gaskets below the fuel level on the Carter/Edelbrock-? They don't leak.

I've run a lot of Holleys on my car. A 390 and a couple 600 cfm 4bbl's. A 500 cfm 2 bbl Holley. I've got a 390 Double pumper, and a Quadrajet from a 318. Haven't played with those two yet. Probably won't use the 390.
The engine is modded up pretty well; A 10.7:1 long rod stroker.
Nothing even touches how that 500 cfm 2300 pulled. It was insane. It also had two modes of operation. Idle and WOT. Cruise had a gremlin that could be moved around, but not erradicated. It made the car annoying to drive on the street, and drank gobs of fuel.

I put the 500 cfm Carter AFB on there, and haven't touched it since. The only change was to decrease the pump shot. Now there's a new one. Usually a slant wants a bigger shot since the vacuum drops out so quickly with a 4 bbl. I run the base jets and metering rods.

Holley's are fun, but I have enough hobbies.

CJ

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Part of Tyrde-Browne Racing

Edelbrock +1
Frank

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Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

The new carbs are this way...Backtracking through some ancient paperwork it looks like original Carter 4 barrel Carb factory flow data up through the late 60's was given in cfm @2"wg... A number of "other brands" using the WCFB and early AFB are this way...Some research indicates Carter probably abandoned this practice in the early 70's, so they could compare to Holley "apples to apples..." So my bad on the Edelbrock vs. Carter flow rates...

-D.Idiot

So I'm thinking the Edlebrock, I like the idea of bolting straight on without too many issues. And I will enjoy adjusting the carb, means I get to learn a new skill and have some fun.

It's now between that and the 350 holley, but having read the online article I believe Doug D was a part of....? I think I'll go the 500.

Will only do this though after I've done the valve job and compression, and I've checked the engine over properly.

Thanks all very much!