Gentlemen, I’m looking for advice on what fuel system to run on a Gm crate 383. I’m not too concerned with hood clearance. It’s either a carburetor and HEI setup or go with some type of fuel injection. It’s just a cruiser so I’m not racing it. Please in your opinion which would you choose and why . Thanks, Dave

 

I would look into ACES EFI and their kits.

 

Do you already have the crate engine? Are you doing the work yourself?

If you add the price of a nice EFI system to a crate engine, you may exceed the price of an LS swap.

But if money is no object, and you already have the engine you want, I would 100% do some flavor of EFI.

 

EFI will require a high pressure fuel system from the tank to the fuel rail. So, depending on what you want.
I run a simple EFI and a separate ignition system.
I'm extremely happy with it.
There are just so many ways to go nowadays.
Both carburetor and EFI can net you good results.
But I truly believe that efi will deliver the best driving experience. No choke, no warm up, instant starts. Superior drive ability.
And no, not everyone wants a LS in a vintage car.

 

I have recently come across 3 or 4 people taking out aftermarket fuel injection units and switching back to carburetors. Each for different reasons.

I don't know if others are coming across this personally I think these systems are poorly engineered

 

The newer Holley EFI systems are really nice and very customizable for the engine you are using. After using a Holley Stealth Sniper on my 427 I am thinking about the next generation of Fuel Injection system for my BB. You can now choose a nice and flat intake manifold with injector holes drilled and tapped. Then you buy a "dry" throttle body and a Holley Terminator or Dominator EFI Controller to do the magic. You could have a nice multi-port fuel injection system that is reliable and idles smoothly and makes cleaner emissions.

When you get ready to buy an EFI system be sure to talk with the various suppliers and see who will help you with your installation AFTER the sale. I chose a company who sold the brand I wanted and the best parts was they offered 24 months of tech support AFTER the sale. Buying the parts was easy, getting everything working 100% after installation is more important and frequently the challenging part of the conversion.

When you have a moment take a look at the Holley Downloadable software. I have used this software on many occasions, it allows me to tailor the system to my Engine. I also have a full time lap top connection for data logging. The Holley EFI systems were well designed and are very nice pieces.

efisystempro.com is the company I speak of and they will get you a great price with awesome tech support. Before the parts arrived in 2 days the tech called me up and introduced himself. He gave me his email address and his Cell phone number and told me to call whenever I needed any help. He is an Expert in the Holley EFI systems and this keeps you from having to call the Holley Tech support lines and waiting for help to show up.

 

It's great to know such a well engineered system has caused other businesses to flourish to help correct defects or deficiencies in the original products..
I'm sure these people can help get things operating better but at what cost?

 

I just built a 383 for my 81. Put a TKX behind it and had Lars help me source a Qjet core that he built to my specs and it screams. I am in Colorado and have no cold start issues with temps down into the 20s. But I also wanted simplicity and some sense of originality.

 

And unbelievable reliability. .

 

My local corvette service shop will no longer install Snipers on C3s. Too many conflicts.
They use & recommend a Holley Terminator X with a 4150 look alike throttle body.
Advantages: better fit, better software, more tuneable, separate ECM, 4150 look alike, etc.

 

Switching to EFI whether the Sniper platform or the more advanced Terminator / Dominator etc, is going to require a level of engagement beyond a carburetor. If you are going to an aftermarket EFI system on our C3s and expect a carburetor experience, DO NOT CONVERT. Additionally, if you are going to pay someone else to dial in your EFI on your Gen 1 SBC or BBC, DO NOT CONVERT. The EFI experience is only worth it if you are going to engage the technology, diagnose and tune your own vehicle. These systems add complexity to a relatively simple platform. So don't expect everything to work correct right out of the box.

I would say that most of the aftermarket EFI problems relate to installation and tuning execution. The "technology" isn't new - it fundamentally is operating right now on millions of cars with millions of miles of reliability. The fuel injectors are the LS3 small injectors, the throttle body is simply a modified carb design, the O2 sensors are the same O2 sensors that are in millions of cars today. Those things aren't "bad tech". It's how we have to install them on our older cars that weren't designed for clean power, or under hood temperatures, etc...

I agree with many, that the ECU should not be in the throttle body design. That means all of the Snipers (1 or 2) should probably be avoided. Go with the Terminator systems OR the ACES EFI which sell a Sniper like product with an external ECU. They sell other EFI products as well, we're focused on the throttle body EFI design.

EFI is only right for you if you engage the features, learn how to tune it, and work through the specific challenges your car will bring to that particular system. If you can't or don't want to do these things, you'll either enrich your "mechanic" or frustrate both of you. I talk to a lot of people that have converted to EFI, and one thing I believe is constant about the experience: those who really learn it and perfect it, universally won't go back to a carburetor. Those who treat EFI like a carburetor, generally go back to a carburetor. In the end, it's a personal choice, and you have to figure out what your own expectations from the EFI experience are.

KT

 

I concur. If I was changing engines nowadays I'd go LS. But no matter what I would go EFI. It ain't rocket surgery and it works like a dream.

 

I have seen this also but often I see evidence to show the issues are self inflicted as folk think they can bolt these on and go and they just dont work that way. Plus there a lot more to install incorrectly and a lot more that can go wrong. and at the end of the day they are a lot more advanced than a carb setup and thats just not for everyone. Especially for a lot of the non tech type folks that install them because they wanted the car to just fire up cold and run like their Toyota.. Thier "car guy" might be better with a carb and just not want to deal with it. I am a member of 2 aces support forums on facebook and the self inflicted issues are often painful to read about. Of course its always the manufacturers "fault" and when the real issue is pointed out or they are asked to check something and report back they usually disappear.

OP if you do consider the aces, get the newer killshot 2 its designed to work with the stock or drop base type air cleaners and it has other improvements. I regret getting the regular killshot myself since I cant use it with my custom CAI. (My fault for not doing more research on the throttlebody size not working with most air cleaners) still not sure what im going to do. Aces told me I was SOL even though my system is new in the box since I bought it more than 90 days ago... They offered me a $300 discount if I traded it in but I paid them $900 for the system so..

 

But 85% of the time you cant just bolt them on and go without additional tuning needed by someone who has taken the time to become knowledgeable on them and for some thats more than they want for a cruiser they drive a handful of times a year. The rewards are great once its setup right though.

 

Good to know!

The Accufab 4150 is exactly what I got for my LS6 swap. Still not 100% sure it will fit under the hood with the stock dual-snorkel air cleaner assembly, but I'm optimistic.
https://accufabracing.com/product/fo...throttle-body/

I'm using a Holley 300-137 intake for the LS, of course, But they make similar intakes for SBCs, and the Accufab TB should be the same. Made in USA!

 

There seems to be a group of people that feel these aftermarket systems work better with single plane intakes rather than dual planes.

 

For multiport yes, for TBI Ive seen this also, Even though most of the oem TBI systems used dual plane intakes. I have found many also claim a dual plane with the center diver cut down seems to work best like the rpm or air gap or an open spacer.

 

I'm a big fan of the low profile single planes with the TBI platforms. I feel they work better because of the people I've talked to, and I've installed both on the same 385 stroker with the same TBI system (Sniper 1). I've "felt" them both in the seat of the pants, and I've tuned them both with the same EFI setup. The dual plane was the Edelbrock air gap - with the slotted divider, and the single plane was (and still is) the Weiand Team G. In my personal experience I felt no loss of torque but the Weiand responded better as RPM came up. If I truly felt that the air gap performed and tuned better than the Weiand, the air gap would have been reinstalled - but it's not - someone else owns it now.

I say all this based upon my experience and some others that I talk to related to EFI applications. However, I would add that the difference although perceivable in my engine combination, it wasn't mind blowing. I wouldn't advise a manifold change if someone had a good tune and a well running dual plane air gap manifold. It also depends on the build. I advise it if you are trying to decide which way to go with EFI / TBI. Users are generally surprised in a slightly positive way when going to a low rise single plane and TBI. It can tune better as well, but that is not universal. Other factors can affect tuneability.

Both air gap style manifolds, dual plane and single, work well with TBI. I just believe that the internet over amplifies the negative aspects of a single plane with TBI more because of carburetor carryover than actual real world driving experiences.

KT

 

Since you have actual experience with both im inclined to believe that experience, at least with the fuel injection system your running.
I researched this a bit and found that this seems to also depends on the design of the throttle body. From what ive been reading Aces accounted for this by recessing some ports and moving things on the base of it so the throttlebody and no one has complained of the lack of response or issues with a dual plane as many forums discussing the sniper do. I would think also they may have made changed to the sniper 2 but I really dont know. I intend on trying out my air gap clone intake ive ported and going from there. I may go with a very low profile single plane which would give up some power as a compromise or I may sell my killshot and get the killshot 2 or something different at this point as im aggravated that is wont work with most air cleaners without spacers.

 

augiedoggy,
You are my source for Aces. I called them with some questions, and they responded well. I like what I see, but am less familiar with the software. I even downloaded it to see, but until I really use it, I must rely on others...

Remember, I am not really saying that there is a significant difference between a good dual plane like the air gap and a good low rise single plane. I'm just saying for some, they might be surprised that the negatives are negligible, and the positives are tangible.