I currently have a 1984 chevy pickup witht the 4 spd manual transmission, stock 350, not a dually, and stock size tires.  It has a eidlebrock carb, came with the truck, has stock exhaust.  It get 10 mpg on the highway.  I would like to get better gas milage, It was intended to be my hunting, wood hauling work truck, but at 10 mpg unloaded, it makes it very expensive to run.  Is there away to get a 5 spd tranny?  Any other options to improve it thanks.  

I am not sure how much a 5 speed would help.  Is it lifted with taller gears?  10 actually aint so bad.  I would guess the best you will get would be like 12 or 13 with one of those.  I have a 1979 and I have not driven it enough to know.  Does it have 4wd.  If it stll has all time 4wd you could put on an aftermarket kit so you can have part time 4wd.  I am not the most knowledgeable but there are some guys on here that can give tips.  Like Snoman or Mudb8.  Anyway, good luck.

Kev  

you can goto a nv4500 5spd tranny, I have never seen enough of a gain in mileage by removing the full time hubs, in fact the kit that is required makes the t-case weak....a camshaft can also help.

the carb takes us to drawn out discusion of the past couple days....on a stock and slightly warmed up engine, the carb needs to be no larger than 600cfm...the edelbrock you have could be the major problem with your mileage..even though they are excellent carbs, smaller is better.  

mudb8-.:
you can goto a nv4500 5spd tranny, I have never seen enough of a gain in mileage by removing the full time hubs, in fact the kit that is required makes the t-case weak....a camshaft can also help.

the carb takes us to drawn out discusion of the past couple days....on a stock and slightly warmed up engine, the carb needs to be no larger than 600cfm...the edelbrock you have could be the major problem with your mileage..even though they are excellent carbs, smaller is better.

A few things here. First, there was no Full Time 4x4 case used in any GM truck and 84 and next, even when they had full time (73 to 79) it was only with a automatic, not a manual. On his MPG, how the truck is configured plays a big roll here. If it is lifted with big knobby tires it is going to eat some gas. Many years ago I had a 72 GMC 3/4 tom with a 350 and 4 speed that I got when it was two years old. I drove it ten years and cross country a few times too. I put about 150 K on it. It would get 14 to 15 on highway if you stayed under 70 or so and if you pushed it to 80 to 85 it got about 13 MPG. It was stock too with stock 16 inch split rims and 10 ply bias plied 32 inch tires. In 73 when emissions kicked in they cut compression ratio and retarded timing and its curve and this cut power and MPG. You can try advancing base line timing to about 8 or 10 BTDC but the catch is it will likely not like 87 octane but given that at todays prices you would only have to see a .3 or so MPG improvement (based on your MPG) for it to cost same and any MPG more means it would be cheaper to drive. BTW, I have a newer 89 4x4 burb that I bought new and it has over 180K on it. It is stock except for a flow master on a 3 inch single exhaust and timing is set 8 BTDC and it burns 89 in winter and 93 in summer. It will make 17 to 18 MPG on long trips all the time (we only use it for family trips these days ) using A/C too.  Recently my son had his car totaled and I went up and hauled it back on a trailer using the old burb and got a little over 13 MPG while towing the car on a trailer!! (trailer and car was close to 6000 lbs)  

check the size of your carb to because on my truck i had a 650cfm on a bone stock 350 and it would hardly run so i put a 500 on it and now it runs great.  

Tyler__820:
check the size of your carb to because on my truck i had a 650cfm on a bone stock 350 and it would hardly run so i put a 500 on it and now it runs great.

Too big a aftermarket carb can indeed hurt MPG.  

klx300a6:
I currently have a 1984 chevy pickup witht the 4 spd manual transmission, stock 350, not a dually, and stock size tires.  It has a eidlebrock carb, came with the truck, has stock exhaust.  It get 10 mpg on the highway.  I would like to get better gas milage, It was intended to be my hunting, wood hauling work truck, but at 10 mpg unloaded, it makes it very expensive to run.  Is there away to get a 5 spd tranny?  Any other options to improve it thanks.

It has 4wd, I am not sure on what size the carb is.  It is not lifted.  I took a 120 mile trip and used 12 gallons of gas.  Where can you fingd the nv4500 transmission.  It has part time 4wd.  It doesn't have a/c.    I am not sure what gearing it has.  

In glove box there will be a axle ratio code like GU6, GT4 or GT5. Also, a NV4500 is not a bolt in. It will require some adapting and it is longer too. Start with engine timing, left stock it will us more gas because it is retarded for emission reasons. Also is this a 1/2 ton or 3/4 ton?  (LD or HD emissions)  

Put as tall a 10ply tire as will fit,jack the psi to near max. its gonna ride stink,but the increased diameter will lower rpms, A tall hard skinny farmer street tread type tire is what ime talking bout.not much help off road,but with some finesse.itle work most places,but then again it is a 5k lb truck.good luck for ya,and happy wheelin!  

I MADE THE MISTAKE OF ASKING FOR 10PLY TIRES AND THE THE TIRE SHOP AIRED THEM TO THE MAX 85PSI AND MAN LET ME TELL YOU IT FELT LIKE THE WHOLE TRUCK WAS ON ICE SKATES!
10 PLY IS MEANT FOR CARRYING HEAVY LOADS NOT TO PLAY AROUND W/ON A DAILY DRIVER THAT DOESNT SEE ANY HAULING!
I AIR MY 10 PLYS TO 55PSI AND MY SKATING PROBLEM WNT AWAY!...6 PLY IS THE MOST I WOULD USE IF HAULING CAMPING GEAR OR WHAT HAVE YOU FOR THE WEEKEND JAUNTS,BUT DO MAKE SURE THAT THE PSI IS UP AND NOT DOWN  

AND W/OUT REGEARING, A TALLER TIRE MAY SLOW DOWN THE RPM AT 65MPH BUT IT TAKES MORE GOGO JUICE TO GET IT MOVING...  

yea.it will change your driving habits.i ran my 10 ply's at 65psi and they were fairly skinny.i am used to the ride of a 18 wheeler,so thats why it wasnt a prob to me.but the milder a tread is and taller and the stiffer the side wall(less distortion=movement=less rolling resistance)the better the probability ofmilage gains.the durometer ratings,the harder to a point, the better,  

If you drive a small block chevy you detter get used to bad gas milage. been driving chevys chevys for over 20 years havent found one to get good milage yet.            good luck !!!  

on my 74 c10 chevy i rebuilt a 350 for my first time and was pumping about 300hp, the best i got out of it in town was 15mpg then it went to about 7-8 mpg on the interstate because of the t350 tranny

on my 86 sub 4x4 w/350 i tuned it up rebuilt the Qjet on it and played with it to fine tune it and the best i got out of it was 15-16 mpg which isnt too bad considering a 6" lift and tires...but sadly sold it...  

build for torque peak at rpm ya gonna cruise it at speed,is that a decent idea???