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 Post subject: EFI conversion?
PostPosted: November 29th, 2017, 4:35 pm 
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GTC Owner
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Joined: May 10th, 2011, 8:46 am
Posts: 312
I'm curious to see if anyone in the group has replaced the carburetor with EFI. I'm strongly considering it but am having a hard time with the required fuel return line. I've never dropped the fuel tank, which I think is about the only way to do it right.


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 Post subject: Re: EFI conversion?
PostPosted: November 29th, 2017, 10:42 pm 
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Joined: March 14th, 2016, 10:38 am
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I looked into EFI but realized these modifications produced the same MPG my rig already was getting. My research eventually led me to a youtube video of a popular cable series on mild performance builds (cannot remember the show). The episode in question covered the Dodge 360 and how it was an excellent engine for moving more air through the intake while increasing the exhaust to a 3" along with blending the intake and exhaust ports. They experimented with a different cam, valves, a low profile 4 barrel manifold, a two barrel carb. & matching adapter plate with a TBI (throttle bore injection) kit (in a closed loop system). Peak torque was lowered around 700 RPMs. HP increased slightly.

This may not be what you are considering, I originally thought about it. They used a kit that included the carb., O2 sensor, computer module, adapter plate and other associated parts. most kits range from $750-$1100.00, minus the other components. I took my Hall out early one morning (4:00 A.M.) and drove it on the freeway at 50 mph to see if lower RPMs gave me better mileage. I have a 2 1/2" header exhaust. It actually made the MPG worse.

Affordable Injection, or summit racing are some sources for the TBI system. My neighbor with his newer Dodge magnum 360 PU, fuel injection gets 12 mpg all the time.


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 Post subject: Re: EFI conversion?
PostPosted: November 30th, 2017, 3:48 pm 
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Posts: 312
I think I've looked at about every offering there is for TBI, including Affordable, Holley Sniper, MTD and Fitech. There are others as well but they're way too expensive for my budget. I've also had numerous discussions with people who've made the switch and almost all of them seem to think that the advantages unquestionably include better cold weather starting, better hot weather starting, high altitude operation without running rich, no vapor lock and much better low end torque (acceleration). I was hoping to hear that mileage was better too, but that might be just a bit better or maybe a wash. All the kits are in the $1,200. + range I think, once you get all the bits required. The Holley appears to be the best of the bunch from what I've read. The big issue for me, aside from the cost, is where and how to run the fuel return line to the tank. I've been looking at the Fitech Fuel Command Center, which is pretty cool, but finding an accessible mounting spot is a real problem, since it has to be mounted in the vertical position, is 6.25" in diameter and around 7" deep. The only spot that looks even remotely doable is right behind the radiator bulkhead on the (vehicle's) right below the AC filter/drier. Way down in there, and then I have a potential bomb in my lap in a collision. Or maybe I'm being paranoid. Dropping the tank seems like a hell of a job since I have the big 50 gallon plate steel version. What to do????


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 Post subject: Re: EFI conversion?
PostPosted: December 1st, 2017, 12:01 pm 
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I wanted to also add that I have 3" exhaust all the way back, SS headers, Edelbrock Performer intake, free-flow muffler and a Performer 1400 carb. None of this seems to have increased the fuel economy much, but it does have good power. I haven't been able to tune out the idiosyncratic issues that all carburetors have, and I've been working at it for 7 years. Correct timing is an issue for me, since I installed a new torque converter along with the reman 727 that the installer failed to put timing marks on and there's no way to see the front timing marks on Dodge B series cab and chassis. Maybe I could do it with mirrors while someone else marks the ring gear?

I DID find a way to run a return line though, by installing a T at the tank drain plug, which is located at the bottom right front of the tank and very accessible. I'm a little leery about the prospect of removing the plug with gas in the tank and might have to use a transfer pump.


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 Post subject: Re: EFI conversion?
PostPosted: December 3rd, 2017, 3:17 pm 
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Joined: March 14th, 2016, 10:38 am
Posts: 12
I purchased a magnetic mirror from Amazon.com. This was mounted on the engine block so that a flashlight/timing light would show the timing scale next to the crankshaft pully. My engine was rebuilt a couple of decades ago. Plugging the vacuum advance and lowering the idle, or adjusting the fuel mixture would not bring the pully mark into the correct position of the timing scale. I have to assume that an after-market flywheel was installed on the engine at some point in past.

I changed the timing by 'feel' several times and left the adjustment where it seemed to perform the best. The original wiper wash reservoir was broken a long time ago by past owner's attempts to cram a test light into the small space available. New plugs properly gapped and all my other efforts amounted to very little in the change of the over-all performance of the engine....


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 Post subject: Re: EFI conversion?
PostPosted: December 4th, 2017, 12:55 pm 
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Joined: May 10th, 2011, 8:46 am
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I'm with you. I've adjusted timing by feel, trial and terror many times but I end up with either no power or pinging. :-( I also have downshift issues, as in it won't, unless I'm going slowly. If the timing is advanced (too far), it downshifts just fine. From all I've managed to overlearn about EFI, one benefit is the timing control being done by the ECU instead of vacuum and mechanical advance.

I also like the idea of installing an electric fan and losing the noisy and somewhat ineffective mechanical fan and clutch assembly and having it controlled by the ECU as well. There are many modern developments that are far better than what was available in 1973 and I think the EFI system is one of em.

I like the magnetic mirror idea!


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 Post subject: Re: EFI conversion?
PostPosted: December 7th, 2017, 12:53 am 
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Joined: December 4th, 2013, 11:55 am
Posts: 154
sniper efi systems sells a whole unit for holley performance...i dont know if its applicable to our dodge motor buts its worth a look...the whole kit is pretty reasonable..id
love to do it.....https://www.holley.com/


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 Post subject: Re: EFI conversion?
PostPosted: December 8th, 2017, 6:29 pm 
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Joined: May 10th, 2011, 8:46 am
Posts: 312
Thanks for the tip! I'd never heard of this model before you mentioned it, and it does seem to be the ideal carburetor replacement for our vehicles. Good to 350 HP instead of >500, 2 barrel instead of 4 and a little cheaper= just right! I'm a little bummed about having spent a lot of time and money on Edelbrock bits and pieces and almost with I'd just kept the original boat anchor iron intake, but they do have an adaptor plate for under $20.00 that should work just fine. They even have these things in stock. Gulp.


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