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73-87 Chevy _ GMC Trucks => Performance => Topic started by: cocop on January 23, 2004, 09:45:00 pm

Title: Mileage not what I thought!!
Post by: cocop on January 23, 2004, 09:45:00 pm
I just had a completely rebuilt 350cid w/RV cam, bored .030 over installed in my 77 GMC 2wd. I also put on a new Edelbrock performer EPS manifold and Edelbrock 1406 carb. The ole truck has a 4:12 rear end and TH350 transmssion. The carb has the standard jets and metering rods.
My problem is the thing gets really lousy mileage. Any suggestions? By the way I live @6000ft. elevation.>:  

Title: Re: Mileage not what I thought!!
Post by: TORQUERULES on January 25, 2004, 12:33:00 am
I have a 350 040 over, wieand 8004 intake 1406 eddy carb(perdy much out of the box), 270/280 204/212 .420/.442" BlueRacer RV cam flowtech headers and dual 2.5" flowmasters. 3.73:1 rear gears.
I live @ 600feet.

I get 11mpg. The engine was a fresh rebuild a year and 4 days ago.

I recurved my distributor. so far it improved mileage by 1.25mpg 9.75mpg to now 11mpg.

That $18.36 part(installed myself) if the improvement keeps up. Will save me about $432/year. :rollin

I'm going to put a electric fan in my truck. see if that improves mileage much. I will because the solid steel fan puts a bit of load on my motor.

Mileage is worse in winter. because run the motor an extra 10-15min per drive around. 15min of motor running without moving burn fuel without racking up miles.


Title: Re: Mileage not what I thought!!
Post by: 77bowtie on February 10, 2004, 10:08:00 am
I'm up here at 6,000+', and 12.7/13.2 mpg in town. 77 Bonanza k-10 now 2-WD, 355 ci, Offy intake w/1"4-hole spacer 600cfm Holley carb re-jetted for 4,000', Hooker headers, dual exhaust, Summit Racing TH-400 trany, 3.42:1 axle. Just what is your mpg? And what mpg do you want? Sounds like your rear axle ratio may be your main mpg problem. That and maybe re-jetting your carb a bit.
I do a bit of towing 25' camp trailer, and my truck with both gas tanks full and a fiberglass shell on weights out at 5,400+ lbs. So I'm happy with my mpg!  

Title: mileage
Post by: pushrod58 on February 27, 2004, 09:12:00 am
Edelbrocks are great,but not for good mileage.I have one on my 1927 ford rod with stock 305 chevy.It weighs 2200 lbs.has high gears and still only gets 10 mpg.Car is rarely drove so mileage is not an issue.On a daily driver pickup I would get a stock 2bbl carb from local parts store.It should help a lot.