#1  
Old 04-15-2024, 06:46 PM
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Default QUESTIONS ON ADDING EFI TO MY '66 389 GTO

I have a question for this forum.
I have 1966 389 tri-power engine right now in my GTO.
It has been bored out to a 400. no crazy cams.
Basically a stock engine when it was built by my engine guy.

I would like an EFI tri-power carb set.
Questions:
1. Do I need a new intake?
2. What kind of fuel pump would I need?
3. Would my stock gas tank work? Do I need a return line?
4. Does any one have this set up on their 66 GTO tri-power?
5. What would be the best EFI tri-power?

Thanks guys.
sorry for so many questions.
I know i have more.

Thanks,
FB66

  #2  
Old 04-16-2024, 09:59 AM
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To my knowledge there are only currently two tri-power EFI kits on the market. FiTech and AutoTrend. I don't know a lot about AutoTrend, but they cater traditionally to high end street rods. Their hardware is probably similar to the FiTech, but I have no clue on what kind of engine management they use. If you're going to a stock carbureted type look in an EFI Tri-Power package, the AutoTrend will probably look the part a bit better. That said, expect to probably pay at least double what the FiTech system goes for.

I've answered your other questions belwo.

1. Do I need a new intake? You shouldn't need a new intake and on a stockish engine I wouldn't mess with anything aftermarket.

2. What kind of fuel pump would I need? You should use a quality in-tank pump. For a stockish 389 I would use a TI Automotive Walbro 255. Make sure to buy from an authorized distributor, there's lots of counterfits of these pumps.

3. Would my stock gas tank work? Do I need a return line? It will work, but it's not the best option for an in-tank pump. If you decide to modify the original tank, I would look at something like the Tanks Inc PA series which adds a small, but important internal sump. There is also the Aeromotive Phantom kit which is decent if this car is only a cruiser and isn't seeing strong drag strip runs or lots of turns. Resist the urge to try and use a frame-mounted fuel pump or one of those under-hood auxiliary reservoirs. In regards to a return line, plan on running new fuel lines front to back. You'll want something in the 3/8" or -6AN size. For either the FiTech or AutoTrend setup you'll need a fuel pressure regulator as well. I don't know what pressure the AutoTrend unit runs on, but the FiTech runs on 4bar pressure (58psi). That means you can run the "Corvette" filter and pressure regulator. That filter has the feed, regulator, filter and return built in to it and is an off the shelf OEM part. You can mount it near the tank and run a short return line, with a single feed line to the engine. Done correctly, you can make this type of setup look almost like factory.

4. Does any one have this set up on their 66 GTO tri-power? I see lots of the FiTech units out and about and have a FiTech myself. All of the software and hardware is primarily the same, it's just in a different form factor. I also see the AutoTrend stuff on a lot of cars around here by virtue of being located close to Pinkees Hot Rod Shop. I have no direct experience with their systems however. My FiTech has been on my car and running for a decade.

5. What would be the best EFI tri-power? I wouldn't hesitate to go with the FiTech Tri Power setup. The only thing that would steer me to spend more on the AutoTrend is if there was a need to get as close as possible to the factory type look. I would take the money saved there and put it towards a brand new fuel system that included a new EFI ready fuel tank from somebody like Tanks Inc or Rick's Tanks and a well thought out and installed fuel system.

I can't emphasize this enough, it's the fuel system that makes or breaks these things. 90% of the problems that come up with these TBI units is related to improper installation and poor half-assed fuel systems.

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  #3  
Old 04-16-2024, 09:18 PM
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WOW! Jason,
Thank you very much! That was very kind of you to provide very detailed information.
I need to start my shopping list.
I am sure I will have more questions later.
Thanks
FB66

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Old 04-16-2024, 09:19 PM
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WOW! Jason,
Thank you very much! That was very kind of you to provide very detailed information.
I need to start my shopping list.
I am sure I will have more questions later.
Thanks
FB66

  #5  
Old 04-16-2024, 09:50 PM
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Does the FI Tech tripower have rochester carb bases? Or is it set of for the Holley 2 barrels like the new aluminum tri-power intakes?

Normally I tell people that aftermarket fuel injection does not make economic sense IF you are only using it as a carb replacement. Meaning that if you arent going to take advantage of the other perks like spark control, or electronic overdrive control, I wouldn't do it.

However, the tri power set up might be an exception to the rule when you consider how pricey tri-power carbs are, and how easy it is to buy the wrong ones and end up with a boondoggle. That might be a situation where it makes sense to go FI even if its just a carb replacement.

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Old 04-17-2024, 01:20 AM
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If you're not wedded to a tri-power setup, I just put a Holley Sniper 2 on my 66 GTO with hyperspark. I used the holley muscle car fuel module which is all in tank with a hydramat and wired/tuned it all up myself. The car has never driven better and was super simple to do.

If you are wedded to it, I think Tin Indian Performance does a kit for tri-power.
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Old 04-17-2024, 09:43 AM
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Tin Indian uses the FiTech system on their TriPower setups that last I knew. I don't think it's a one-off part.

The FiTech TriPower is supposed to be a Holley 2300 flange. However, there are reports that this isn't quite right. I believe they likely made the throttle bodies in such a way as to try and achieve fitment on most make tri-power and six packs. Depending on the setup of the intake manifold, it may be necessary to enlarge the bolt holes on the throttle bodies to get them to sit correctly.

Tin Indian would actually be a good shop to discuss this with, and possibly even purchase the setup from. They've done a lot of testing on this and they've got a lot of parts for it, including some adapter plates as well.

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Old 04-19-2024, 08:00 AM
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Quote:
Originally Posted by JLMounce View Post

I can't emphasize this enough, it's the fuel system that makes or breaks these things. 90% of the problems that come up with these TBI units is related to improper installation and poor half-assed fuel systems.
This is the biggest take away. So many failed EFI setups out there are due to a cheap fuel system. Can't say that enough. Unfortunately these systems are commonly advertised with reservoir tanks or external add on pumps to make the entry level price look more appealing to the consumer. That's exactly the wrong way to do it.
Take the time and spend the money to do the fuel system properly with a good in tank pump setup and you'll thank yourself later.

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Old 04-20-2024, 12:59 AM
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I find the opposite over this side of the pond. Fuel supply is actually quite easy and most get it right IF they spend the right dollars in the right areas. What brings most cars undone here is when people ONLY rely on the fuel side and don't let the ECU handle the spark side OR there is EMI noise, usually from poor or not well planned wiring, that creates issues with sensors or causes the ECU to reset and do silly things like that - or the tuner is just horrible and doesn't understand true modelling and just relies on closed loop.

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Old 04-21-2024, 09:23 AM
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Guys are cheap over here Kris They won't spend money on the fuel system.

But I hear ya, I see about the same amount of poor install issues that cause all kinds of drivability issues, and most of that is subpar wiring. Some of it is just the old wiring in the 60 year old car, or people not finding a good clean source for the pink wire. Sadly though a lot of that stuff gets wrongly blamed on the EFI unit.

I'll just give an example on the fuel system stuff. A bunch of years ago when FAST had their EFI unit, I think this was before Holley and FiTech really took off, I installed a FAST setup on a 57 Tbird for a guy. Happens to be my neighbor. Of course he was cheap when it came to fuel delivery and just wanted an external pump mounted at the tank with a vette style regulator/filter. After all that's how they advertise these entry level EFI's to keep the price attractive so it must be okay right? LOL
I advised against it as I've had plenty of experience with external electric pumps using carbs with just 6-8 psi, knowing they don't like heat and extended run time, they just eventually wear out brushes, get weak and die. If you're lucky and pay attention you see the signs before you get stranded somewhere. If you want reliable transportation it's not the best route. There are a lot of reasons why the OEM's put that stuff in the tank. Of course all that was ignored. So I did as he requested.
Sure enough later that summer driving back from Phoenix the pump got hot and died, left him stranded about 80 miles from home. Needless to say the car came back for a new fuel tank with a nice in tank pump setup and new fuel lines all plumbed properly. That was probably about 15 years ago now, maybe more, and he's still driving the car today with no complaints or issues.

So these days when a car comes in and wants an EFI install, I just tell them up front what it's going to need for a fuel system and be prepared to add another $1000 to the price tag. If they bulk at that I tell them I'm not your guy and kindly turn them away. I'm done with putting my name on something that I know is just going to either perform subpar or simply just fail down the road, because somehow it ends up being all my fault

Now for some guys they may go for 2-3 years before they see an issue with those quickie fuel systems, keeping in mind they don't even drive 1000 miles a year, while others won't even get through the summer here in Arizona. They just roll the dice, but eventually they'll be revisiting that fuel system at some point.

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