Gain extra benefits by becoming a Supporting Member Click here find out how!
Silver
Gold ***Platinum***
50chev1067 (2)Don H (5)Runningon6zonk2ajoda (6)
ShoeboxTOMD45 buscobill
1963SBHD (4)Dean50 (8)Backyardbuild jumbojim (3)
InkaholicMike (3)
Classic Performance Products
Ciadella Interiors American Auto Wire Art Morrison.com
Exile® Battery Keeper™ 6/12 volt charger w/ LED battery monitor
Hellwig Products IncPerformance Rod & Custom
Impala Bob's Bob's Chevy Trucks Bob's Chevelle Parts Bob's Classic Chevy

  >> Switch to Mobile Version <<

Recent Hot Topics
Current Quote
"Let's ALL do what we can to TOOT THE HORN for ChevyTalk - OUR BOWTIE BROTHERHOOD IS THE BEST ON THE 'NET!!!"
~ Supporting Member
Recent Topics
Join the Community today
**
New ** Easy eBay Search Tool







Username Post: '79 C10 fuel econ and transmitions        (Topic#279918)
lukezx7r 
Forum Newbie
Posts: 18

Reg: 03-08-11
04-19-12 10:16 AM - Post#2216903    

first question... i have a '79 C10 crate 350 V8 small block. the carb... its an edelbrock... but i dont have any numbers on it at the moment. i wanted to know what sort of numbers people get for gas milage. want to know what i should be expecting. in the winter i was getting like 10.5-11 then in the spring i started getting about 13ish. now its back down to about 10-11. any thoughts? second question... it has the stock three speed trans (on the column) converted to a floor stick... is there a different transmition out there that would make a significant improvement in economy? a stick on the floor trans?
so, any thoughts as to why my gas milage fluctuates so much? is 11 where it should be is 13 more where it should be? if those are low, what are some things to fix/ clean to get those numbers up? and is there a pug-n-play floor trans that would be worth swaping out?

thanks in advance everyone,
luke

Edited by lukezx7r on 04-19-12 10:25 AM. Reason for edit: No reason given.

 
John 
Chevytalk Moderator & "3rd Year" Gold Supporting Member
Posts: 7196
John
Age: 45
Loc: Montgomery, AL
Reg: 01-15-02
04-19-12 05:36 PM - Post#2217050    
    In response to lukezx7r

Luke, you could put a 700R4 and 3.73 gears in but you'd spend most of two grand on that to try to get another mile per gallon. If it were me, I'd get a good quadrajet from a reputable shop and spend money or your time towards getting the engine tuned up, the front end lined up if needed, and air the tires up the most you can without wearing the centers out.
1979 2wd K5 Blazer, 350/TH350
1985 4x4 M1009 K5 Blazer, 6.2/TH400


 
Vaughn 
"12th Year" Gold Supporting Member
Posts: 15257

Loc: Colorado Springs, CO
Reg: 08-08-04
04-20-12 01:02 PM - Post#2217302    
    In response to John

A 5 speed overdrive will cost you a minimum of $1500 - and there are lots of people out looking for them - so you probably won't find one.

Automatics - specifically the 700r4 - are available with overdrive, but you will have to hook up the TV cable properly (WHICH IS CRITICAL TO THE LIFE OF THE TRANS) with an aftermarket linkage, and you will have to install a means to shift it - whether that means installing another steering column to get the stock shift linkage, or buying an aftermarket floor shifter and cable to do this. This also will cost you about $1500 for a GOOD trans. You will have to shorten the driveshaft and get an output yoke from a 700r4 to graft onto your shortened driveshaft.

Or, you could go to the junkyard and find a rear end with a numerically lower gear ratio, and swap out the entire rear end. This is the cheapest method, it will cost you about $200 or so to buy another rear end. This will do the same thing as adding overdrive. It will cause you to lose off-the-line power, but will increase your gas mileage.

DO NOT try to swap just the rear gears out of the current rear end, because rear gear setup is different for every rear end, you will have to have the experience and the proper tools to do that (which you probably do not have - most people do not, even if they are experienced mechanics). Gear setup costs will run you $500 or more. Swap the entire rear end instead, most people can do this fairly easily.

A tune up will help, but will not significantly increase mileage the way a change in gear ratio will, if the motor is already in good shape. It will improve up to 1-3 mpg to tune it.

 
technitom 
Contributor
Posts: 248
technitom
Age: 46
Loc: Near Cincinnati, OH
Reg: 12-01-11
04-21-12 10:24 AM - Post#2217566    
    In response to Vaughn

proper timing and carb tune/balance is essential to pick up some mpgs...

new plugs and good wires (I recommend ac delco r45ts starting off).

make sure your cap and rotor are good.

set initial timing at 12 degrees (with vac advance hose unplugged at the advance, and plug up hose running to carb/manifold)...

then hook your vac advance line back up, it SHOULD run from the advance to manifold vacuum instead of ported vacuum.

finally use a vacuum gauge to T into the vacuum advance line... you should be pulling 15-22"...

set you idle around 800 rpm in park. adjust you primary a/f, one side at a time, adjust IN until you see vacuum drop on gauge, slowly adjust OUT until it reaches MAX vacuum, then do other side of carb. take your time. small adjustments, give time for adjustments to come into effect.

when you think you are close, goose the throttle and let it settle back down. check your idle rpms and adjust if necessary. go back and forth side to side making tiny adjustments if necessary, slight goose of throttle between adjustments, let settle before adjusting again.

you JUST want to reach max vacuum, not go any further or you are wasting fuel.

personally, at that point, I turn the screws back in 1/4 turn to lean it out a smidge.

GOOD LUCK

Words are a lot like toothpaste... Once its out of the tube,
there's no getting it back in...


 
lukezx7r 
Forum Newbie
Posts: 18

Reg: 03-08-11
04-23-12 07:24 AM - Post#2218194    
    In response to technitom

its been a while since its been tuned up.... im sure that could help some. as soon as it warms up a bit more up hear ill have to get after that. we'll have to wait and see how that goes. was still wondering if there was any more folks out there who could give me a ball park on the gas milage they are getting with their '79ish C10. does everyone agree with the 15-22 mentioned above? Mines been fluctuating dramatically down to 10 up to just about 14... with almost no change in driving situations. i know i shold tune it up but am i in the ball park and if not... where should i expect to get?
thanks in advance to anyone who can help and thanks to those who have added their thoughts thus far... they are much appreciated.
luke

Edited by lukezx7r on 04-23-12 07:29 AM. Reason for edit: No reason given.

 
Vaughn 
"12th Year" Gold Supporting Member
Posts: 15257

Loc: Colorado Springs, CO
Reg: 08-08-04
04-23-12 11:34 AM - Post#2218261    
    In response to lukezx7r

18 to 20 highway is the best you can reasonably expect with a stock th350 trans and the lowest stock numerical gear ratio, with a v-8 motor in the best tune possible.

22 is possible, but most people will not be able to achieve it.

 
hargdude 
Forum Newbie
Posts: 21

Loc: Texas
Reg: 01-18-10
05-02-12 04:57 AM - Post#2221439    
    In response to lukezx7r

I believe the 15-22 technitom is talking about is vacuum not mpg.
Checkout this link on how to use a vacuum gauge is helpful for tuning.
http://www.secondchancegarage.com/public/186.cfm


 
technitom 
Contributor
Posts: 248
technitom
Age: 46
Loc: Near Cincinnati, OH
Reg: 12-01-11
05-04-12 04:40 PM - Post#2222489    
    In response to hargdude

yeah, sorry for the confusion, I meant pulling 15-22 inches of vacuum on the gauge

Words are a lot like toothpaste... Once its out of the tube,
there's no getting it back in...


 
Vaughn 
"12th Year" Gold Supporting Member
Posts: 15257

Loc: Colorado Springs, CO
Reg: 08-08-04
05-05-12 11:27 AM - Post#2222756    
    In response to technitom

If you still want a manual floor shift overdrive trans, you might consider this:

http://albuquerque.craigslist.org/pts/2865034353.h...

This is a mopar 833 floor shift manual trans, that was installed in certain 6 cylinder dusters in the late 70s. It has basically 3 forward gears and an overdrive 4th gear (actually 3rd and 4th were swapped, 4th was 1:1 and 3rd was the overdrive gear). SOME of these transmissions had a muncie pattern (which means that it might bolt right up to the GM bellhousing) - but you have to make sure that it does, otherwise you will have to get a conversion adapter.

This was a rare transmission, it is highly sought after by the Mopar crowd. It also means that if you blow it up, you will never find parts for it - so if you do get it, don't beat on it.

 
Icon Legend Permissions Topic Options
Report Post

Quote Post

Quick Reply

Print Topic

Email Topic

1624 Views
FusionBB
FusionBB™ Version 2.1
©2003-2006 InteractivePHP, Inc.
Execution time: 1.893 seconds.   Total Queries: 13   Zlib Compression is on.
All times are (GMT -0800) Pacific. Current time is 09:58 PM
Top