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Carburetors

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Cool53:
This is going to start a war, Mike. At least it usually does.
First of all, if you are really into performance and you are going to run a carburetor then you are going to run a Holley style carburetor. If you are a hard and fast supporter of Carter (Edelbrock) style carburetors then we aren't going to have much to talk about. I guess one way to look at it is if you go to any racing event where cars are winning then they are running Holleys. That is unless they are restricted by ruled to run something else, like a Quadrajet.
If you are going to be concerned about performance then you are owing to buy a good carburetor. Holley has some nice stuff, and Quick Fuel is doing ok for manufactured carbs . But I buy ALL my carbs from AED in Richmond, VA.
AED is one of the best. They won 3 out of 4 events at the carb shoot out at PRI two or three years ago, took 2nd place in the fourth category. John Dickey who has now sold he company to his employees, kept every tune up he ever made. You order a carb from AED and it 's going to be close enough that most people won't need to do much screw turning, or jet changing at all.
You need to have access to or install an Air Fuel meter of some sort to see just where you are. I work with Innovate, who has just been bought by JE Pistons. My friend Leigh and I supply Innovate with the brackets they sell for mounting a TPS on a 4150 Holley. Then they sell them yo everyone else.
Instead of me talking I guess it would be better to field questions. I usually run a little rich at idle for good drivability, around 12:1, and about 12.6 at WOT, which is conservative. That keeps things safe for the street. But at the track I shoot for closer to 13.0:1 to 13.2:1 for a little more power. That's where keeping notes helps. Air density plays a big factor in which jets to run. Keep your float levels good and high so you can leave from near an idle then flash the converter, make sure any time you change throttle opening front or rear test you readjust the accelerator pumps. Make sure your timing is where it should be (another topic for later).  99% of the carburetor issues are timing problems really. And timing will kill an engine much sooner that carb tuning will.
All the new good carbs come with lots of adjustment, but if you get a good one then it's like Mike says, there's not all that much to it. And if you want a carb with a choke then you aren't really looking for all tad performance you can get. AEDs don't have choked or vacuum secondaries.
With two circuits carbs like the 4150 you are using the fuel from the Ickes virus unit got transition fuel las well, so many times a hesitation can be fixed on a Holley style 2 circuit carb with a simple idle mixture adjustment.
I like that all the new perf carbs have 4 corner idle. With 2 idle screws the fuel in the secondary side of the carb never got used if the driver didn't open Tate secondaries on a regular basis that's why the secondary fuel bowls look so bad on some cars.
Ok, let me have it!!!

MIDROAD:
You'll get no argument from me. I love Holleys.
I have to own up to using a pair of 500 cfm Edelbrocks on the '29 Chevy tourer in my avatar but only because on old Offenhauser manifolds there is no room for Holleys and a distributor. They work OK in this application, easy to tune and never leak. I would not use them on any serious performance engine however.
I agree with tuning slightly rich, much easier to use on the street. I found by experience the only method of tuning your engine is driving it. Engine or chassis dyno's can only set a base. Then you need either track time or road time.
There are a lot of carburettor guys in Australia but most have preconceived ideas. If you are capable of building an engine with all the right parts you will be able to tune it with a bit of common sense.
Years ago I worked with a very smart guy who only used a compression tester, timing light and exhaust gas analyser  in that order to set engines for maximum power and driveability.
On a streeter driveability is one of the most important issues. If you build that 8000 RPM SBC I mentioned in an earliar post you are wasting your money. It would be better to invest in more cubic inches.
I always use mechanical secondary 4 corner idle carbs and usually find if I've picked the right size they don't need much adjustment. They should always be checked before fitting, most need precise adjustment to the linkages and accellerator pump arm clearance.
Your right, Timing is critical. Most people have no idea. Maybe it's because so many of them only have experience on pollution engines and don't know how or won't set carbs and timing to let them rev. I spent my younger years doing cam, exhaust and carb changes on all types of pollution engines and they all ran cleaner and better with improved economy.

Cool53:
I'm not building an 8,000 rpm sbc, I will shift it around 7,200. I am a firm believer in switching to a bbc after 400 inches. A small big block is preferable to a big small block in my history, especially where cylinder heads are concerned.
On another note, I had the privilege of a phone conversation with Paul Ray at Gilmore Engineering (Penske's Engine shop for Indy car). Indy cars are still required to run valve springs. The parts they use are so light that they have no trouble maintaining 16,000 rpm. I would like to see a video of that on a Spintron.

themoose:

What you guys are saying is definitely interesting and informative but for most guys in the real world who have built a nice hot rod on a strict budget I think they're most interested in a  car is able to perform well on the street, run smoothly and capable of giving a nice kick when the go pedal occasionally tickles the floor. Talk to us about how to set up that old Holley 3310 to get the most out of it. You can gather a lot of information by reading your plugs if you know what your looking for and what the procedure is. And how about choosing the correct jets, power valve and accelerator pumps. Walk the guys through the basics of what it takes to properly set up a carburetor without using a bunch of sophisticated equipment and still get the desired result.

Hey Jef...Don't get me wrong. I like playing with the high tech stuff too so keep it coming!!

Moose

MIDROAD:
Moose, I was talking about street engines. The fact that I prefer mechanical secondary carbs does not mean a 3310 Holley is the wrong choice. They are a good street carb. Most street engines need a dual plane manifold for low RPM torque and if you have a SBC capable of up to say 400 HP a new, not old 3310 should work fine with maybe only minor jet changes.
Again, make sure everything is adjusted correctly before fitting. Holley's own website has the info needed.
   Mike.

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