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1958 GMC 1/2t truck , GMC 302 ,3 speed transmission

Looking at upgrading to EFI. Either Fitech or Holley.

Any advice-

If the ignition current draw is high, use a relay. HEI works fine in my 302, use a relay for power.

Ed

EFI Ed not HEI.

EFI- Electronic Fuel Injection

Anytime one can precisely control the fuel supplied to an ICE is an improvement. In this case your ROI may not be worth the effort as the head design will limit a throttle body EFI as it does a carb. Long intake runners with lots of bends into siamesed intake ports, low compression and a low redline combine as some of the limiting factors.
That said you could possibly squeeze out a little more power & MPG and get a more dependable fuel delivery system which may make it worth while to you.
Value is in the eye of the beholder, or something like that.
Good luck
Dave

With a little tinkering and a huge amount of programming knowledge, you could use a dummy Rochester B as a throttle body and install an injector in each of the three intake ports, then trigger the injectors three times per crankshaft revolution. It would even be possible to install a second trigger device in a stock-appearing distributor to pulse each injector a fraction of a turn of the crankshaft before one of the intake valves open, for sequential port injection. Add a feedback circuit and an oxygen sensor, and you can fine-tune the mixture at whatever frequency the computer clock runs, usually either 10 or 90 hertz. The technology is out there, and has been for 30 years or so- - - -it's just a matter of adapting it to a 1920's design engine.
Jerry

Could it be done like the original throttle body mounted injectors? I may be way off here, but I thought our '84 Pontiac with the Quad 4 had a single injector mounted in a carb looking unit... to the naked eye seemed to spray a continuous mist down the throat.

I have a friend that has a throttle body injection on a 1950 Buick straight eight that works well. The Buick head is the same design as the six cylinder Chevy---lousy manifold design, crappy head design, and siamesed ports with the main difference being it has two more cylinders. I built him a computer controlled HEI distributor which ties into the injector controller and it worked much better than the separate systems. A PM will get you his name and phone number.

Any feedback on the Fitech. Can I use the original line from the tank to the inline fuel pump? Should I get the Command Center ?

A few of the local car buffs are running the FiTech set ups on their "80's vintage GM rides. Every one of them is very happy with the units, super simple to install and set up. All are running the fuel command center as its way easier than the alternative. Of course those are all V8 engines that came with 4 barrel carbs which is what the FiTech is designed to replace. You'll need to drop off a few hundred dollars with Clifford performance for an intake to mount the FiTech to your 302. A few more to redo your exhaust and another couple for ancillary items such as manifold heat, air cleaner, gaskets...

Steve

Ok I already have a 12bolt.com modified Holley 4150 installed using a Clifford 4 barrel Intake , Clifford Headers. My GMC Nicson Headers just came in yesterday

I've been doing a little reading on such a conversion on a V8.
The basics would be the same for your 302.
Edelbrock makes a conversion kit (Pro Flo 3 EFI) for a 4 bbl manifold. e). They also offer a downstream fuel sump that works with the high pressure fuel pump which alleviates the need for a return line. You do have to run an additional vent line which the article I read taps into the fuel filler neck. You'll have to drill and tap a couple ports in the intake and exhaust manifolds for sensors

Theres a pretty good article in the latest Classic Truck mag covering their adaption of EFI to a SBF.

Holley also makes a neat 4bbl to EFI conversion kit.

Both utilize self learning CPU's that can be customized to your liking.

Sounds like you've got the basics covered.
Good luck
Dave

Just received my Classic Truck magazine.Will read the article.

I'm a FiTech fan. Replaced a new Carter 625 cfm carb (after repeated efforts to make an older Carter 625 and a AVS I had on the shelf work) with a 400 hp rated FiTech and it's GREAT.

The vehicle (notice I didn't say car ) is the V8 "rig" in my sig. Main issue I had to solve was fuel boiling in the carb due to the engine compartments high heat (small underhood area, full of V8) the ethanol contaminated gasoline caused fuel to boil at low speed. FI completely solved that problem. MPG improved and the seat of pants dyno says hp increase too. That along with instant starts and great idle to wot response with no hesitation makes it a win/win.

On the return line, I used the original fuel line for the return and ran a new nickle copper fuel supply line. Easy. I really don't see any reason to spend the money or clutter up the engine compartment with FiTech's Commander (eliminates the need for return line) system.

Good Luck reguardless of the system you use.

RonR

Nope, you didn’t say “Car” but you did say Miata and the last I checked that wasn’t the name of a Chevy/gmc Truck!

Thanks 4 the feedback.

Danny,

The chevytalk forum has a section dedicated specifically to your issue:

https://www.chevytalk.org/fusionbb/showforum.php?fid/35/keyword/Fuel_Injection/

On chevytalk the "Chevy High Performance Topics" moderator, handle "Grumpyvette", answers questions with a brief summary statement and also links to a lot of published articles on whatever the subject is. It's a great forum for people who like to thoroughly investigate whatever they're working on at the moment.

Here's a typical example of a Grumpy summary statement:

"I run into so many guys that think you can just un-package new cylinder heads and slap them on any engine they build , and expect those heads to function flawlessly.
there is almost always at least an extra 15-hp-20-hp or more potentially easily accessed through minor port clean-up.
if your willing to disassemble the heads, port match the runners and clear up the casting flaws and smooth and contour the bowl area under the valves you could rather easily double or in some cases triple those potential power gains just by improving the port contours and removing casting flaws."

It is followed by a long list of links to further explain the concept. His stuff is great reading for people who really want to understand what's going on inside an engine and how to make improvements.

Well can't argue that, so via the magic of the edit button the post now reads "rig" Synonym for truck, including Chevrolet and GMC. Per the Southern Man's online dictionary by RonR

Ray , Thanks I didn't think to check there although I am a member