Fuel Inj. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Nichboy · 05-14-2002, 03:08 PM

71 SWB with a 5 yr. old crate 350 in it. This 8 mpg is about to kill me. What all is involved in converting this eng. to fuel injection. Thanks

DennyB · 05-14-2002, 03:13 PM

If gas milage is your main concern, an over-drive trans and/or higher rear gears is your best bet for the money!

------------------
Toms River NJ
(Transplanted Hoosier)

56 working Street Rod(under construction 71-2 coil chassis)
Give a man a fish and he will eat for a day. Teach him how to fish and he will sit in a boat & drink beer all day.

Big69C20 Toy · 05-14-2002, 03:14 PM

Umm 8mpg? that sound really low to anyone else out there? Perhaps the motor needs a real good tune up, that or it's one heck of a built motor and that's the economy yer supposed to be getting.

------------------
69 Custom 20, 396BB,Longbed fleetside.
New Oak Bed With SS strips.

Edelbrock performer RPM-O, Edelbrock 750Carb, Headers, HEI, 2 40" glasspacks.
Stereo: Classic-style tape deck/radio, 2 6x9 Cerwin Vega's in doors, 2 10" Neo subs under seats, 1 900 Watt amp.

SN= Ares220 on AIM.

Located in Beautiful Southern Cali or Michigan when i'm at school.

DennyB · 05-14-2002, 03:20 PM

Big69C20 Toy,
My 71 C20 with a 307, 3-on-the-tree and 4.57 rear got 9 mpg

It turned 3600 rpms at 70 mph! (not practical)
My 91 S10 with a 4.3/700R4 turns 2000 rpm in o/d and 2800 rpm in 3rd

Big69C20 Toy · 05-14-2002, 03:46 PM

Yeah i hear you but that just seems VERY low to me for a smallblock, i could see possibly with such tall gears but jeez. I get 10mpg outa my BB with 4.10 gears and a th400. I can drive it 100 or 50 and i still get 10mpg. 8 just seems too low for a mild smallblock

------------------
69 Custom 20, 396BB,Longbed fleetside.
New Oak Bed With SS strips.

Edelbrock performer RPM-O, Edelbrock 750Carb, Headers, HEI, 2 40" glasspacks.
Stereo: Classic-style tape deck/radio, 2 6x9 Cerwin Vega's in doors, 2 10" Neo subs under seats, 1 900 Watt amp.

SN= Ares220 on AIM.

Located in Beautiful Southern Cali or Michigan when i'm at school.

tom hand · 05-14-2002, 03:57 PM

8 mpg sounds low but 10 is about normal in these trucks if you have a heavy foot. If the speedometer is off a few miles per hour,there is no easy way to check the mpg anyway.

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72 GMC Sierra SWB almost finished---- 84 Softail
Olive Branch MS

ckhd · 05-14-2002, 04:00 PM

Something is wrong. My '69 four wheel drive swb, 350, 4-speed, 3.73 gears, 31" tires & quadrajet got 20 when it was running right. 15 was the worst it got.

My '68 that weighs 5300lbs and has 4.57s and a 4-speed gets 7-8mpg...

Fuel injection may fix it, because it sounds to me like your carb is crap, or something else, or maybe lots of stuff. Fuel injection may not fix it, if say, you have a worn out tranny that's slipping a lot, or theres something wrong in your distributor, etc...

------------------
Bowen
'68 K20 fleet
'69 K10 swb fleet
'72 C10 lwb step
'72 K10 Suburban

DennyB · 05-14-2002, 06:12 PM

Its all gearing, 4.56, 4.57 gears or lower and its no longer a highway machine.
4.10s may not sound like much of a difference but it is exp. when were only talking a few mpg difference.

superchevy · 05-14-2002, 06:49 PM

Swap in a 700R4 trans.
SC

Cheyenne Super · 05-14-2002, 07:11 PM

To answer your question it is not that difficult. Edelbrock offers a few different options. check thier website for details. but the prices range from about 1400 to 2000 dollars depending on what setup you use. I personally get the same mileage with a mild 350 heavy foot and overly rich carb. Holley also makes some fuel injection kits but I haven't really read the details on them.

[This message has been edited by Cheyenne Super (edited May 14, 2002).]

Mike C · 05-14-2002, 07:53 PM

The auto trans is killing you. Manual trans will get you at a minimum 12 w/out changing anything else. Same with the TH700. Just expensive... Tune the hell out of it. Get a 1200 rpm stall converter and a set of 3.07 gears and you can probably get the 12-14 that way. My built 327 with 4.11 gears and 35" tires gets 14 mpg, but you can thank the SM465 for that...

------------------
70 GMC 3/4 ton Sierra Grande 402/TH400
72 Jimmy 4WD 4spd 4" & 35's
64 Corvette Coupe
68 Camaro 'vert TPI & TH700
69 Z/28 355 12.6's @110
72 Datsun 240Z-ol' reliable

da-burb · 05-14-2002, 10:28 PM

On the trip to Pigeon Forge I kept track of my burb's mpg. The best it did was 14.5mpg between Indianapolis and Knoxville Tn and the worst it did was 9 mpg.

I feel that I drove it the same way all 1100 miles. I averaged 63 miles per hour with gas stops, lunches on the run and bathroom breaks. Some of it could be the terrain or wind, but I think most of it is gas quality. My worst mpg came while driving on the flatest land. Well I take that back. It seems like I could only get 100 miles out of a tank on the winding mountain roads in the Smokies.

------------------
1971 C-10 Suburban
1972 C-10 Suburban
1969 XL Galaxie Fastback
1968 Galaxie 500 Fastback
1974 SCOUT II

Montrose, Minnesota

05-14-2002, 03:08 PM	#1
Nichboy Registered User Join Date: Jun 2001 Location: Oklahoma City Oklahoma Posts: 173	Fuel Inj. 71 SWB with a 5 yr. old crate 350 in it. This 8 mpg is about to kill me. What all is involved in converting this eng. to fuel injection. Thanks __________________ 1971 Chevy SWB Oklahoma City, Oklahoma

05-14-2002, 03:13 PM	#2
DennyB Led Sled! Discs R 4 ME! Join Date: Jan 2001 Location: Toms River, NJ, USA (Transplanted Hoosier) Posts: 7,327	If gas milage is your main concern, an over-drive trans and/or higher rear gears is your best bet for the money! ------------------ Toms River NJ (Transplanted Hoosier) 56 working Street Rod(under construction 71-2 coil chassis) Give a man a fish and he will eat for a day. Teach him how to fish and he will sit in a boat & drink beer all day. __________________ "Never ride faster than your Angel can fly" I.M.O.M,W,J&C Patriot Guard Rider

05-14-2002, 03:14 PM	#3
Big69C20 Toy Livin' it up. Join Date: Nov 2001 Location: Richland, MI Posts: 2,212	Umm 8mpg? that sound really low to anyone else out there? Perhaps the motor needs a real good tune up, that or it's one heck of a built motor and that's the economy yer supposed to be getting. ------------------ 69 Custom 20, 396BB,Longbed fleetside. New Oak Bed With SS strips. Edelbrock performer RPM-O, Edelbrock 750Carb, Headers, HEI, 2 40" glasspacks. Stereo: Classic-style tape deck/radio, 2 6x9 Cerwin Vega's in doors, 2 10" Neo subs under seats, 1 900 Watt amp. SN= Ares220 on AIM. Located in Beautiful Southern Cali or Michigan when i'm at school. __________________ -Greg; Sold the 69 C20. It's off to a better home with more love! Now onto the 86 CUCV M1009; K5 blazer with 6.2L diesel, corp 10 bolt axles, Detroit locker in the rear, trutrac front, 3.73 gears, 35" tires.

05-14-2002, 03:20 PM	#4
DennyB Led Sled! Discs R 4 ME! Join Date: Jan 2001 Location: Toms River, NJ, USA (Transplanted Hoosier) Posts: 7,327	Big69C20 Toy, My 71 C20 with a 307, 3-on-the-tree and 4.57 rear got 9 mpg It turned 3600 rpms at 70 mph! (not practical) My 91 S10 with a 4.3/700R4 turns 2000 rpm in o/d and 2800 rpm in 3rd __________________ "Never ride faster than your Angel can fly" I.M.O.M,W,J&C Patriot Guard Rider

05-14-2002, 03:46 PM	#5
Big69C20 Toy Livin' it up. Join Date: Nov 2001 Location: Richland, MI Posts: 2,212	Yeah i hear you but that just seems VERY low to me for a smallblock, i could see possibly with such tall gears but jeez. I get 10mpg outa my BB with 4.10 gears and a th400. I can drive it 100 or 50 and i still get 10mpg. 8 just seems too low for a mild smallblock ------------------ 69 Custom 20, 396BB,Longbed fleetside. New Oak Bed With SS strips. Edelbrock performer RPM-O, Edelbrock 750Carb, Headers, HEI, 2 40" glasspacks. Stereo: Classic-style tape deck/radio, 2 6x9 Cerwin Vega's in doors, 2 10" Neo subs under seats, 1 900 Watt amp. SN= Ares220 on AIM. Located in Beautiful Southern Cali or Michigan when i'm at school. __________________ -Greg; Sold the 69 C20. It's off to a better home with more love! Now onto the 86 CUCV M1009; K5 blazer with 6.2L diesel, corp 10 bolt axles, Detroit locker in the rear, trutrac front, 3.73 gears, 35" tires.

05-14-2002, 03:57 PM	#6
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	8 mpg sounds low but 10 is about normal in these trucks if you have a heavy foot. If the speedometer is off a few miles per hour,there is no easy way to check the mpg anyway. ------------------ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

05-14-2002, 04:00 PM	#7
ckhd Registered User Join Date: Oct 2000 Location: St. Johns, Arizona Posts: 2,660	Something is wrong. My '69 four wheel drive swb, 350, 4-speed, 3.73 gears, 31" tires & quadrajet got 20 when it was running right. 15 was the worst it got. My '68 that weighs 5300lbs and has 4.57s and a 4-speed gets 7-8mpg... Fuel injection may fix it, because it sounds to me like your carb is crap, or something else, or maybe lots of stuff. Fuel injection may not fix it, if say, you have a worn out tranny that's slipping a lot, or theres something wrong in your distributor, etc... ------------------ Bowen '68 K20 fleet '69 K10 swb fleet '72 C10 lwb step '72 K10 Suburban __________________ my 2¢ - t.i.o.l.i. Bowen 1968 K20 fleet 1969 K10 swb fleet 1972 K10 Suburban 1972 C10 lwb step 1992 K1500 'burb 1995 K2500 'burb 1997 C1500 'burb 1999 K1500 2000 K1500 'burb Why do I own so many Suburbans?

05-14-2002, 06:12 PM	#8
DennyB Led Sled! Discs R 4 ME! Join Date: Jan 2001 Location: Toms River, NJ, USA (Transplanted Hoosier) Posts: 7,327	Its all gearing, 4.56, 4.57 gears or lower and its no longer a highway machine. 4.10s may not sound like much of a difference but it is exp. when were only talking a few mpg difference. __________________ "Never ride faster than your Angel can fly" I.M.O.M,W,J&C Patriot Guard Rider

05-14-2002, 06:49 PM	#9
superchevy Got big-block? Join Date: Jul 2000 Location: Austin, Texas Posts: 2,453	Swap in a 700R4 trans. SC __________________ '68 CST SWB factory 396/T400 buddy buckets, a/c, ps, pb '72 Corvette convertible 454/4spd/ac, ps, pb '73 GMC Sierra Grande short wide 454/T400 ps, pb, ac '77 K5 Blazer black on red, 350/T350/NP205 ps, pb, ac all original '78 GMC Sierra Classic short wide 454/T400 ps, pb, ac '72 GMC Sprint SP454. 1 of 38 built. '73 GMC Sprint SP454. 1 of 71 built. '75 GMC Sprint SP454. 1 of 25 built. SOLD! '72 GMC K25 4x4 468/4L80e/NP205 build thread http://67-72chevytrucks.com/vboard/s...23#post4324423 SOLD!'55 Chevy gasser 496/4spd build thread http://67-72chevytrucks.com/vboard/s...96#post4324396

05-14-2002, 07:11 PM	#10
Cheyenne Super Registered User Join Date: Mar 2002 Location: Efland, NC Posts: 303	To answer your question it is not that difficult. Edelbrock offers a few different options. check thier website for details. but the prices range from about 1400 to 2000 dollars depending on what setup you use. I personally get the same mileage with a mild 350 heavy foot and overly rich carb. Holley also makes some fuel injection kits but I haven't really read the details on them. [This message has been edited by Cheyenne Super (edited May 14, 2002).] __________________ 1971 Cheyenne Super Soon to be converted to '68 front clip. Efland, NC

05-14-2002, 07:53 PM	#11
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,723	The auto trans is killing you. Manual trans will get you at a minimum 12 w/out changing anything else. Same with the TH700. Just expensive... Tune the hell out of it. Get a 1200 rpm stall converter and a set of 3.07 gears and you can probably get the 12-14 that way. My built 327 with 4.11 gears and 35" tires gets 14 mpg, but you can thank the SM465 for that... ------------------ 70 GMC 3/4 ton Sierra Grande 402/TH400 72 Jimmy 4WD 4spd 4" & 35's 64 Corvette Coupe 68 Camaro 'vert TPI & TH700 69 Z/28 355 12.6's @110 72 Datsun 240Z-ol' reliable __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

05-14-2002, 10:28 PM	#12
da-burb "Ochre Ogre" Join Date: Apr 2000 Location: Springfield, MN Posts: 3,558	On the trip to Pigeon Forge I kept track of my burb's mpg. The best it did was 14.5mpg between Indianapolis and Knoxville Tn and the worst it did was 9 mpg. I feel that I drove it the same way all 1100 miles. I averaged 63 miles per hour with gas stops, lunches on the run and bathroom breaks. Some of it could be the terrain or wind, but I think most of it is gas quality. My worst mpg came while driving on the flatest land. Well I take that back. It seems like I could only get 100 miles out of a tank on the winding mountain roads in the Smokies. ------------------ 1971 C-10 Suburban 1972 C-10 Suburban 1969 XL Galaxie Fastback 1968 Galaxie 500 Fastback 1974 SCOUT II Montrose, Minnesota __________________ Bowtie Truck Stop Inc. Mid-West GM Truck Restoration Parts Supplier Your Key Parts, Auto Metal Direct, Dynacorn, and Goodmark dealer. like us @ www.facebook.com/BowtieTruckStop 1971 C-10 Suburban (Ochre) 1971 K-10 Suburban (Ochre) 1972 C-10 Suburban (Ochre) 1972 K-20 Suburban (Yellow- that just aint right!) Springfield, Minnesota 56087



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