Tech @ BG

What has your chassis dyno guy had to say about this? Looking at your dyno runs, you should have hit your face on the windshield before 7000 the way the HP is falling off.

How hard did it pull, and what RPM did it pull to?

The majority of SBC camshafts will run even or better yet more duration on the exhaust side to help scavange due to the cylinder head design. Running more duration on the intake, wouldn't promote complete cylinder filling, then from there the other events do not seem to be optimal for throttle control / drivaiblity. Have you check your spark plugs to see how they were burning during your dyno pulls?

When you say closed circuit what exactly are you doing with this combination? Is this an oval track car or are you Road Racing? A 200cc runner with only 10-1/4 compression would seem extremely big on an engine of this size. The cam profile doesn’t really make a lot of sense with this size runner either. All of your tuning parts will interchange between ours and Holley’s. The instruction manuals have a fair amount of information, you may be better off actually buying a carburetor tuning book. What did the AFR look like on the dyno? For your power to peak, and roll where it did there almost has to be something seriously wrong with your combination.

v80z, Although your heads may be a touch big for the combination, and the camshaft less than optimal the numbers seem way off. This type of combination should be able to make in the 400 HP range without too much work. A manual transmission shouldn't loose much more than 10% so the numbers are way out of left field. The carburetor is probably a touch big, which can lead to some drivability, and performance issues, however shouldn't be this far off. The other thing this is extremely puzzling is your Peak HP RPM. This would indicate something either severely out of tune (possibly going extremely rich or lean) or something mechanically wrong long a clutch slipping. Do you have any dyno pulls before you changed the carb and intake? Also do you have any of the AFR numbers off of the dyno?

v80z, Can you post a complete list of your engine/driveline specifications?

Don't have specific dimensions yet with air cleaners, as we're working on them as week speak. Once we get closer on them we'll be able to give you the exact dimensions for the different combinations for both the front and rear from the top of the block to the top of the air cleaner.

The one problem with those blocks is that they use a Needle design to change fuel flow. They can cause an engine to go overly lean at WOT.

Thanks for the interest in our new Inline carburetors. We’ll see if we can answer some of the questions, and comments brought up here: Let’s first start off with a standard 4bl carburetor: The 4bl carburetor was designed out of packaging convenience not performance in mind. The first engines had a single (1 barrel) carburetor. As they required more air engine builders added more one barrel carburetors, then for packaging purposes the idea came about to mount all four barrels together. This makes your fuel lines, linkage, etc all much easier, however it leaves you with a problem within the intake manifold. You wind up with 4 longer runners, and 4 shorter runners. This is not real good for distribution. The idea behind putting all 4 barrels inline is first and foremost that we’re able to equalize the length of the runners. This allows use to use the longest runner possible within the shortest height. Our runners go across the intake like an old cross-ram. Since we’ll be using our RS (Replaceable Sleeve) system we’ll be able to offer different sizes to fit most applications from about 500 CFM up to about 1400 CFM. We will also be offering different style boosters to for different applications. The thing that killed the inline Autolite® was the fact that Trans-Am banned them in 1971, and then NASCAR, and NHRA followed suit. Trans-Am told Ford that they needed to make the carburetors available to other manufactures or they would be banned. Ford opted to drop its Trans-Am program. Without racing they had no reason to do more R&D on these setups and they died out. There were not the other aftermarket manufactures as there are today to run with the idea. If you look at the Offy intake that grumpyvette has pictured you can see exactly what we’re talking about. That intake was offered with multiple tops, a single 4bl are one of the other versions to the 2x4 top he shows in his picture. If you were to measure from the runners to the barrels of the carburetors they are different lengths. There is no way to pull the same amount of air through them, so you’re not able to produce the same AFR from cylinder to cylinder and cannot produce the same amount of HP out of each cylinder. Here's a link to video from the SEMA show:

Carburetor Spacers: Carburetors spacers can be a very useful tuning aid when working on your streetcar, or racecar. A spacer can be used to move the torque and power-band where it is more usable in your application, or they can be used to help work out inefficiencies in your combination. 4-Hole Spacers. As a rule of thumb a 4-hole designed spacer (4 individual holes one under each barrel of your carburetor) will increase your throttle response, and acceleration. They can also move the torque and power-band down in the RPM range. This is accomplished by keeping the air and fuel flowing in more of a column, which increases the air velocity. This can be a perfect addition if your vehicles throttle response is not as good as you’d like, or you’re getting passed when you pick up the throttle coming off of the corning. A 4-hole spacer can also help make up for something in the intake tract being larger than optimal (too large of a carburetor, cam, intake, etc.) Open Spacers. As a rule of thumb an open designed spacer (1 big hole underneath your carburetor) will decrease your throttle response, and acceleration. They can also move the torque and power-band up in the RPM range. This is accomplished by increasing the plenum area, which will help in the higher RPM’s. This can be a perfect addition if your vehicle has traction problems when accelerating, or coming off of the corner. A 4-hole spacer can also help make up for something in the intake tract being smaller than optimal (too small of a carburetor, cam, intake, etc.) Combination Spacers. A combination spacer (half 4-hole, and half open) can give you the best of both worlds. Increasing your throttle response, and acceleration over not using a spacer, and increasing or broadening the torque and power-band. Plenum Dividers. A Plenum divider does as the name implies divides the plenum in an open plenum intake manifold from side to side. These are generally used to help prevent fuel slosh from side to side in high G load Oval-Track, or Road-Race applications. It is common on certain engines to have lean cylinders do to fuel slosh. A SBC oval track engine running on methanol can run lean on cylinders 3 & 5 while cylinders 4 & 6 will run rich. A plenum divider can help eliminate this. Spacer thickness. Varying the thickness of your spacer will affect how it affects your engine. Normally the thicker the spacer the more of an affect if will have on your combination. Meaning if a ½†thick spacer helps you a little a 2†thick spacer can give you more of the same affect. Spacer Material. There are many different types of materials used for manufacturing spacers. They all have pro’s and con’s. Wood for example is a great material as far as thermo efficiency, but can wick fuel, which is not safe. Plastic, or composite spacers are also very good at not transferring heat, but are not as strong, and can be harder to modify. Generally Phenolic fiber, or Aluminum is preferred. Phenolic is very good at not transferring heat, but can be hard to modify. Aluminum is not as good at heat dissipation, but can be ported or modified easily to work on specific applications. Spacer Tuning. Since each spacer will react differently on each combination there is not a right or wrong type. Spacers are a great tool to have to help dial in a new combination, or tune your racecar for varying track conditions. Swapping out a spacer is a very simple change that can have great impact on the drivability of your streetcar, or racecar. Having a couple types, and thickness of spacers around is always a good investment.