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Old 03-26-2023, 10:06 AM
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eschaider eschaider is offline
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Join Date: Feb 2006
Location: Gilroy, CA
Cobra Make, Engine: SPF 2291, Whipple Blown & Injected 4V ModMotor
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The choice depends entirely on you and your skill set, along with what you are willing to pay for the skills you don't have. Neither route is cheap; each has its advantages. If you go to the Holley site and select 850 cfm, vacuum secondaries, and an electric choke, the site will present you with a single solution. It is a Holley Speed Demon carburetor with a price tag of $731. Add about $250 to the price tag if you want one of the whizzy double throw down carbs.

To that price tag, you will need to add dyno time, the cost of a competent Holley carb tuner (the real McCoy, not an imposter), and perhaps a hundred bucks or so in toys to bring the carb up to where it needs to be to work properly on your engine. Figure about $1,000 for dyno time. You might get away with less but probably not. When you are done, you will be in the tank for about $2.5K to $3K. The bulk of the money will be spent on services for dyno time and the right carb guru.

If you go the EFI route, while many paths are available, I recommend the DIYAutotune MS3Pro PnP ECU. You can buy it for $1,499, but that is not the end of the road. The Fuel pumps and associated lines are another $1K in round numbers, and the injectors will cost $750, give or take a hundred dollars, depending on where you buy them. Add another $350 for fuel rails. The engine wiring harness the MS3Pro PnP uses is a stock Ford harness, so that saves you some money because you can source it out of Ford, eBay, or a salvage yard. Let's say $350 (or less) for your harness.

Like virtually all aftermarket EFI systems, the MS3Pro comes with both tuning and data logging software, and in the case of the MS3Pro PnP it also has a base tune to get you out of the blocks. If you do not know how to tune and have the current social media imbued, but not useful, tuning skills, you will need to get back to the dyno. This time it should be less expensive than the carburetor stop, but you will still be in the tank for $500 to $700.

A Mass Air Flow based EFI system will start in any weather, and at any altitude with the flick of the key. It will provide you with OEM quality, reliability, repeatability, and driving satisfaction — but all that, not surprisingly, comes at a higher price point than a carburetor-based system.

Relative cost differences: Carb, somewhere between $2,500 and $3,000; EFI, somewhere between $4,500 and $5,000. If you decide to add whistles and bells to either system, the price of poker goes up.

A couple of parting thoughts. The old idea of recurving your ignition advance with springs, weights, and assorted black magic is caveman crude compared to what you can do with EFI. Your ability to specify timing in fractional degrees and precise rpm increments using EFI is simply impossible to reproduce in the old style distributor systems. This comparative difference is pretty much the case across every aspect of tuning the two different systems.

For example, the ability to control your AFR across the entire engine operating range and hold it to your target AFR within a decimal fraction of one AFR is impossible to do with a carb. Additionally, the ability to build into your tune a highway cruising mode where you get 23 to 25 mpg possibly higher without hurting your wide open throttle power production (or the engine) is absolutely impossible to build into the carburetor fueled engine.

In short, the reliability, predictability, drivability, fuel mileage, and horsepower you will be able to produce will be more in line with what you intuitively expect with EFI than with a carb.

There is one final consideration. Today it is becoming increasingly difficult to find knowledgeable carburetor tuners/modifiers. They tend to be old guys at or near end of life. When the few that are left pass on, you will be hard-pressed to find someone to care for the carb — because they will all be dead and buried.

Not so with the EFI service crowd. You might even discover you can learn how to do it yourself with a bit of reading and curiosity — it is far from hard to do and has a much more visible cause-and-effect relationship with what you do and how the engine responds than the carburetted alternative.

The EFI alternative will be more expensive initially and less expensive over the life of your car — and you will discover if you should choose to, that you can easily maintain it yourself. The ante at the poker table will initially be higher for the EFI, and the cost of ownership will be lower in the long term. The driving and ownership experience will be superior but initially more expensive with an EFI election.
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Last edited by eschaider; 03-26-2023 at 11:21 AM.. Reason: Spelling and Grammar
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