'79 GMC Carb to EFI?

[Dune Wolf]

Has anyone replaced their carb with fuel injection? Curious on cost, work, and if it is worth it.

[SKR]

I changed mine over to a Holley Sniper. Cost was $2300, including labor. I went with a rear mount tank and internal pump as well, which I haven't added up the cost of that yet and not sure if I want to know.

Was it worth it? I could buy a lot of gas with what I spent on it. But I was getting 6-8mpg on the highway with the carb, and now I'm getting 13-14 (that's imperial gallons, miles per US gallon would be 10-11). With a 454, TH350 and a 3.08 gear and spinning 2700rpm.

It's supposed to be self learning and somehow it's learned to run rich all the time now, so it's parked until I have time to figure it out. Up until then though it ran pretty good, so if I can get it to unlearn whatever this new trick is I'll be happy. So it's pricey, but it works, but it's not perfect.

[Ziegelsteinfaust]

I helped a friend put a 411 Vortec fuel injection kit into his truck, and all in he spent about $2000. He used alot of Craigslist finds to get it done, and it took about a year before the swap.

He got a suburban that needed a transmission for the parts. Rebuilt the engine/transmission, and put them in his truck with a carb setup he already had. Then he carefully removed the harness, and found a 411 pcm from a van. Purchased a HP tuners kit, and found a single plane with injectors cheap. Fixed that up nice, and made a elbow for the throttle body. Got the throttle body ported, and modified the harness to work with the injectors. Installed some fuel pump into the tank, and began the swap.

Everything bolted up easily, and there was a few snags with tuning. Getting a program that he could modify was the hardest part. Then he just started writing his own stuff till it would run well enough to dial in. Which took a couple days of free time. After that it ran amazing.

It was about a 400/415TQ motor, and it could get 20 pretty easy on the highway. The single plane probably was to big by a bit, and a dual plane would of bumped the torque up quite a bit.

[dieseldawg142]

Edelbrock fi on the 454 in my '85.
hardly any diff in miles per gallon compared to the q-jet (small, very small...)
but driveability is waaay better. no throttle pumping when she's cold, no choke, just reach in and turn the key, nothing else and it fires right up.
as i live in the most mountainous area of north america, fi is also a big plus.
runs exactly the same at 10 000 as it does at sea level
switching to fi to save money??? hahaha.....
all said and done it is still an expensive mod, you'd need to drive a lot to return what you invested
was fairly simple and strait-forward to convert though, i did need to get a cowl induction hood to clear everything (more $$$....)

[Wwes]

Yep, I converted my 83 to a factory style TBI setup. Stripped the underdash and engine harness from a 1988 suburban. Easy to setup and runs good (although I'm still dealing with some timing issues).

It's easy and cost around $600 for the parts. I could do it again in a weekend.

[Dannyboy1966]

I went with the Go EFI 4 from Fitech a year ago, went from 4 to 6 mpg up to 14 or 15, I'm happy with it, especially in cold weather starts. I found that most problems are installer error when there are problems. running it on a stock 350, with sm465 and 373 rear right now, getting ready to throw a 700R4 in it soon.

[HunterRotten]

I can't speak on how efficient it is since my truck is still coming together, but the holley sniper is pretty neat. Starts immediately. I don't have a number on the costs but it wasn't cheap. I converted to dual tanks from an 87 truck, 2 walbro 255 LPH pumps in each tank. Fuel injection line, return line, and the vapor line for both tanks.

If I didnt convert to dual tanks, or change to 87 tanks it would have been significantly cheaper and could be done for the $1000.00 flat. I got the unit from AutoZone on black Friday for like $800.00