350 chevy gas mileage

[kennywright86]

Hey i am new to the site, my name is kenny. i resently bought a 81 CJ7 with a 350 chevy engine and done some research. i have a SR4 trany and 410 gears. i want to make the drive train stronger and help with my gas mileage i dont use it for mud and rocks. i bought it for a hunting buggy. any ideas would help me a lot. Thanks!

 

[biohazard cj]

hey kenny, welcome. well if you are only useing the jeep for hunting and nothing else i would think about doing a trade for a inline 6 like the AMC 258 i6 / 4.2l with a 3 or 4 spd tranny. even a 5 spd if u can find one. then put 305 gear ratio in the axles and you should get upper teens maybe low 20s since you dont need all thos ponys. but thats what i would do. the other thing you can do, is get a holley projection kit from summit or ebay (its a tbi fuel injection ) and i have one on my 360 and im getting 19mpg with 355 ratio 33inch tires. . then you can also do other things for better mpg. its all up to how much money u wanna spend and time u wanna invest .

 

[Old Dog]

tire size info would be nice.
If your still carbed a EFI of some sort will get a coulp mpg's for you.
An Overdrive Transmission will get you a coulpe also.
You didn't say what your getting now.
I also have a 350 but with a 350 auto so same 1:1 gear, 4:10's and 33's I get 10 mpg on the road on a good day going down hill with the wind to my back.

 

[CJ]

Hey kennywright86! Welcome to our site!



I'll be blunt - It's like asking does this 'BRICK' compare to your 'BRICK' mileage.... BRICK mileage all suck!


You own the best off-road vehicle ever built, and it was made 30 or so years ago... Mileage was not an issue then...


Welcome to the CJ world...
(Chev or AMC V8 Both SUCK at mileage)

 

[biohazard cj]

that is a very good way of putting it cj.. im very pleased that i get 20 hwy on a good day. im running fuel injected 360, T-18 tranny, and 3.55 gears on 33 inch tires.


BTW is anyone else haveing a problem iwth the website tonight?

 

[kennywright86]

thanks for the info i got a chevy 4x4 truck out of a junk yard with a bad moter its got a 700r4 im goin to use that trany but not sure bout the gears yet. was thinking bout 3.73 i want it to pull like a 4x4 but get some mpgs. i know i aint goin to get the best. but around 15 to 20 is better than my 9. i got 31 inch tires rite now but will put 33s on it later not going any biger than that.

 

[IOPort51]

if the truth be told, it is less expensive for me to put my CJ on a trailer and pull it with a 1 ton ford diesel if I am going any distance.
I get 12 in the jeep and 14 in the truck.

 

[Old Dog]

if the truth be told, it is less expensive for me to put my CJ on a trailer and pull it with a 1 ton ford diesel if I am going any distance.

Got to agree with that. It's pretty bad when my dodge with a V10 gets better milage pulling my jeep than the jeep gets. They both have 4:10's and 33" tires.

 

[scrambler]

Just a thought... If your already planning on swapping things out ya might want to look into putting a 4.0L in it with the fuel injection, or do the bottom of the AMC 258 i6 / 4.2l with the top off the 4.0, I've heard they'll get ya in the low 20's.

 

[kennywright86]

jeep parts cost a lot so i want to stay with chevy i dont need that 350 i can put a 4.3 in with no prob. and have tbi i got the 700r4 trany but dont know bout what gears to use i dont know any thing about how to match what gears with a 4.3 and 700r4 to get in the uper teens and still have a good 4x4 to hunt out of. it any one can help thanks!

 

[Cheepjeep85]

well i had an s10 with 4.3 and 4l60e (basically a 700r4) it had 3.73 gears in the rear. i got 23 to 25 mpg with it (heavy foot). now you wouldn't get that good with the jeep its heavier and not as aerodynamic. but i think you would do ok with 4.10s.
but if it where me i'd stick with the 350 for power, fuel inject it, and swap in the 700r4 just my opinion

 

[mattmaninthecan]

hey kenny, welcome. well if you are only useing the jeep for hunting and nothing else i would think about doing a trade for a inline 6 like the AMC 258 i6 / 4.2l with a 3 or 4 spd tranny. even a 5 spd if u can find one. then put 305 gear ratio in the axles and you should get upper teens maybe low 20s since you dont need all thos ponys. but thats what i would do. the other thing you can do, is get a holley projection kit from summit or ebay (its a tbi fuel injection ) and i have one on my 360 and im getting 19mpg with 355 ratio 33inch tires. . then you can also do other things for better mpg. its all up to how much money u wanna spend and time u wanna invest .

hi i have the exact jeep that he is talking about here, a AMC 258 i6 / 4.2l CJ7 and its a 5 spd. I am looking to put a 350 chevy engine in it and if you are interested in doing so i would like to work out a trade.

 

[chris77cj]

Have 2 say v8 not very good mileage mine has 350 and 1 ton axles not best mileage but not worst.

 

[Kane]

My last fill up gave me 12.0mpg. I run a modified 350 with a holley 670 truck avenger carb, 10-1 compression and 3.55 gears. I know once I get off my butt and tune the carb better I can net about 14 but that will be about it unless I fuel inject. I would thing a stock 350 with a two barrel or a very small four barrel would do close to the 6 banger.