fuel injection conversion

[silvertip67]

Hi all...I have heard from some other chevy friends about converting carb to fuel injection...

first off is it worth the trouble in gas savings?? I love the old 327 with 4bbl...but the 10-11 1/2mpg is getting a bit hard at thpump...I drive my truck everyday...

any thoughts on value of this??t

[MTCK]

I've got a Holley tbi system on my truck and get about 12 mpg around town. Not any better o. The highway with 4.10 gears and no OD. I'm not sure the efficiency gain is a good enough reason to swap, but the drivability is improved - especially in cold weather. I think the best bet for mpg setup would be a 4.8 or 5.3 motor with overdrive trans. Also if I had to do it again I would use oem fuel injection instead of aftermarket. Tuning takes a lot of time and effort!!!

By the way I think that's awesome that you drive your truck every day!
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[andrewmp6]

With out a over drive trans you might pick up a mile pre gallon or 2.It will start faster and have a little bit better throttle response.How much cfm is the 4 barrel you have on it now?A lot of people run a bigger carb the needed and you burn more fuel then needed.

[Ziegelsteinfaust]

You have a K20, and from my knowledge you probably have 4.11 gears. I have a C20 with 4.11, and I average 14mpg with up to 17mpg hwy. So your not much worse then me.

Like the guy above said fuel injection adds a lot in drive ability, but not so much in fuel economy. Unless you went over board on a carb or it is need of a rebuild.

I would start with a solid OD trans with a lock up converter, and that could get you close to 18-20mpg hwy. Depending on how you drive, condition of the engine, carb, and how much stuff you keep in the bed of your truck. A simple cross bed tool box will kill mpg because of the drag it creates.

[SlammedBlazerLife]

what system works better for 4 wheeling and going down steep grades. Gas mileage is important but what works better for the trail like Moab UT 4x4 obstacles.

[Ziegelsteinfaust]

Originally Posted by SlammedBlazerLife

what system works better for 4 wheeling and going down steep grades. Gas mileage is important but what works better for the trail like Moab UT 4x4 obstacles.

My guess would be a 4L80 with a tight converter so you don't cook the fluid running trails.

But I would split the difference between a low enough first gear effective ratio, and a cruise speed you want to go.

Lets say you have a K20 with 5.13 gears, 35 tires, and a 4L80 with a lock up converter. Your only turning 2400rpm at 70 mph, and from my understanding is not so bad for hill climbing with the right transfercase. Plus the hwy rpm should be just about right for the tires, and a decent 350.

http://www.richmondgear.com/101032.html

I so want a 4x4, but the furthest I go offroad is the 7-11 parking lot.

[silvertip67]

somehow this thread got off track...for me anyway...

my question was if converting to fuel injection was cost effective...I like the 4bbl square jet that is stock...my truck is 98% stock...only thing that isnt are the wheels...I got rid of the split rims...plus I do have radial tires...other than some chrome valve covers...its all original equipment...

my truck @2800 rpms goes 60-63mph...level and flat...thats it...its a '67 K-20 CST...327 w/ square jet carb...411 rear

I talked with another friend and he recomended swithching the rear end from the 411 that is in it now to maybe the next level down...

I use 4wd all the time...but have no plans on anything as HD as Moab...just getting around in the rocky mountains in snow...a few off road trails w/ my slide in camper...

I dont know the exact numbers of the stock chevy differentials...but maybe a 380 something might give me some better gas mileage...1st gear only gets used when I have a load...its a 4 speed...so I always have that for slower engaging in 4wd...

maybe someone out their in internet land has switched those gears with success..I am forgetting the possibility of fuel injection...too much$$ for too little...





thanks...ted

[MTCK]

Sweet truck! Unfortunately regearing both axles will be big bucks too. You'd see a roughly 10% drop in rpm going to 3.73. Have you already done all the cheap stuff? Might try an HEI ignition, make sure your carb is jetted and tuned just right. Also tires can make a bit of difference. I like tall and skinny. 255/85r16 would be a good narrow tire for a truck like yours.
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[Ziegelsteinfaust]

I would go with a 4L80 on your truck before I spent the money of fuel injection.

Fuel injection may get 1mpg over a proper carb set up, but an OD trans could get 3-6mpg depending on a few things.

[makman1297]

I converted my 77 with an 87 tbi system. Best thing I ever did.
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