calling every1 who went 1/2 to 3/4 ton axles!

[bigtruck81]

you'll see no appreciable difference in fuel economy between a 305 and a 350.

with that being said, and knowing you want to keep your trans, you can probably get away with 3.73s and 35s pretty easily. this will likely save you some gas on the highway, but at the cost of some in town milage and get up and go in stop and go traffic. 4.10s seem to be about perfect for 35s with no OD.

[theoneandonly]

I found this caculator a while back and it might help.

http://www.4lo.com/calc/gearratio.htm

[earl87gta]

here is my favorate one http://www.grimmjeeper.com/gears.html

[wibilly]

any body done the math to see how many miles to payoff based on fuel savings alone?

[earl87gta]

Im sure you can get alot of fuel for the little bit of milage you would gain.

[dinotruck68]

ive been thinking, my truck already has pretty low gearing in the axles, i dont how low but i can definately tell while driving.. so to run 35's cant i just run my gearing as is.. or get lower gears for the 10 an 12 bolt and sum stronger shafts?????

[ND_guy]

Stats:
1967 K20 SM465, 4.56 pumpkins, 35" tires

Old engine:
400sb, Qjet 9mpg hwy.

New engine:
305TBI 14mpg Hwy.

I get 14mpg at 2900rpm at 60mph.

!If I drive 65 at 3200rpm I get 12mpg.!

Overall gearing does play a role in mileage, but
SPEED KILLS MILEAGE slow down

Our aerodynamics kills economy.

[earl87gta]

1968 burb 283 with sm465 4:56 gears and 36in tire 10 MPG at 60.
new drive train is 6.2 deisel and nv4500 and 4;56 gears cant wait to beable to tell you the new milage but its not back on the road yet.

[dinotruck68]

i dont know what tbi is but it sounds like its working for ya.. cant wait to hear about that new drive train Earl keep me filled in..

Ive been thinking about converting my 305 to run on propane , my dad had a 72 4x4 with a 350 runnin on propane bak in the 90's an he said it ran real strong, just the big tank was kinda ugly lol! just another thing ive been thinkin about since i plan on bigger tires an axles an such

[earl87gta]

TBI throttle body injection its what most GM trucks had threw the 90s looks like a carb with 2 fuel injectors.
A lot of the jeep guys run propane I thought about adding a propane injection system to my d-max .
The 6.2 should be fun Im trying to get some restaurants to donate there used cooking oil to me to burn in it.

[68K20 x Drill]

My friend has an 84 4x4 on propane with 700R and super high gears, 32's, I think it gets 18 highway.
Earl you want to be picky about the oil you get. it should be non hydrogenated, and if you can get them to prefilter it for you through a 'shortening strainer' that will be a huge plus for you. I've done a few of these conversions if you have any questions.

[dinotruck68]

my uncle did the propane injection on his 04 3500 4x4.. dont know the specs an such are but it sure is fast... since propane is pretty cheap i thought it would be a good thing to consider for my truck, its also better for the life of your engine, it burns cleaner to

[72cheyennesuper20]

Originally Posted by msgross

if you are running 35's with any axles then don't worry about gas mileage... gears, tranny, engine, carb etc.. will all play a big part but don't ever expect over 13 MPG i would guess.

13 MPG, I wish.

[earl87gta]

non hydrogenated whats that I guess I have some more reading to do. Im sure when I start the convertion Ill be posting alot to get every thing working.

[extd56]

I will be running a 91 454 TBI with a 4L80E trans and 35" tires with 3.73 gearing. It should be right around 1800 RPM's on the freeway so I will see what kind of mileage I will get. It will be in a 69 3/4 ton crew cab longbed with a 6" lift so I am not expecting too much, hence the 32 gallon fuel tank.

[bigtruck81]

any more pics of your rig? havent seen a 4 door of that vintage before.

[earl87gta]

Originally Posted by bigtruck81

any more pics of your rig? havent seen a 4 door of that vintage before.

I hope you have some time on your hands one of the coolest build ever.

http://67-72chevytrucks.com/vboard/s...d.php?t=188993

[padresag]

Hi; I am am going back to a small block in my 64 4x4 panel. I have had a 453 detroit in it for 17 years. The PO was the one that did the install and threw away the old frame brkts. I am looking for the passenger side eng frame brkt if you are interested in selling it or know where I can find one. I noticed that it was a 283. as long as it isn't a 292 i6 r/s I am ok. 230-250 i6 r/s is fine to
thks
ron
I do run an independent 205 behind it. you can get an independent r/s case from a light duty IHC or dodge trucks and flip in the gears from a ford if need be. the ford is left hand while the others are r/hand. I think that I paid $100.00 for everything that came with the t/c from a 72 scout inc the shifter, mind you that was 15 or 16 years ago. I do also have compltete parts listings for both a t221 and a 205 if you need