What could i possibly get for MPG with these two setups?

[DustyNova]

Possible Setup 1: 400 SBC 1989 k30 crew cab half ton axels and suspension under it 4 inch lift 33 inch tires 700r4 Throttle Body Injected 373 gearing

Possible Setup 2: 454 BBC 1989 k30 crew cab half ton axels and suspension under it 4 inch lift 33 inch tires 700r4 Throttle Body Injected 4.10 gearing TBI

Possible Setup 3: 1987 k10 383 stroker 700r4 373 gearing TBI 4 inch lift 34 inch tires

[piecesparts]

Simple answer LOW!

If driving on the road and city streets, then the taller tires will make you work a little. The best gearing for the tall tires is the 4.10 gears. Bigger truck and taller tires will work your engine to get up to speed.

[DustyNova]

my dad has a k10 85 with a good carb sbc 400 and 700r4 it really isnt that bad on gas for an older truck its tires are like 315 75 16 and the gears are 373 it at least hits 12 in the city dunno bout highway its only like 14 or so

[rich weyand]

Those are kind of weird setups. I think the bbc would tolerate the 3.73 better than either of the sbcs, but with 33" tires, I would definitely go 4.11 on any of them.

TBI will give you better mileage than the carb setup DustyNova is talking about. I dunno. I think with the sbcs you would probably get 14-18 because of the overdrive and the TBI.

Put a carb 350 on there without overdrive and you are looking at 10-12. That number I know for sure!

[andrewmp6]

Half ton axles in a 1 ton should be a crime lol.If you care about mileage go diesel a 6.2/6.5 can bolt in easy or a 12 valve cummins swap.The cummins swap will cost more and need swap parts but can bolt in with all the swap parts.

[DustyNova]

Originally Posted by andrewmp6

Half ton axles in a 1 ton should be a crime lol.If you care about mileage go diesel a 6.2/6.5 can bolt in easy or a 12 valve cummins swap.The cummins swap will cost more and need swap parts but can bolt in with all the swap parts.

Diesel cost a bit around here more than gas not sure why i like the frame of the 1 ton but the suspension of a half or 3/4 ton XD

[Ziegelsteinfaust]

Originally Posted by DustyNova

Diesel cost a bit around here more than gas not sure why i like the frame of the 1 ton but the suspension of a half or 3/4 ton XD

I think a diesel would get more then enough mpg to justify the higher cost of fuel.

Other then that if I could of put a OD trans in my K20 I would of run 4.11's so I wouldn't lug on the highway. Not sure of which type of tires you plan to run, but my AT's need some rpm to keep the engine happy. More so with a SBC then the BBC.

[DustyNova]

Originally Posted by Ziegelsteinfaust

I think a diesel would get more then enough mpg to justify the higher cost of fuel.

Other then that if I could of put a OD trans in my K20 I would of run 4.11's so I wouldn't lug on the highway. Not sure of which type of tires you plan to run, but my AT's need some rpm to keep the engine happy. More so with a SBC then the BBC.

i wanted to convert a k30 to shortbed with 4.11 gears and half ton suspension under it with a 4 inch lift and bf goodrich A/T tires probably around 33-34 inchers and a overdirve tranny with a sbc 400

[PunishedC10]

I had a small block 400 with a holley efi intake on a '89 sw slammed 2wd. It was a nightmare, I could never get it dialed in correctly. Either way, I don't think you're looking at a good mpg setup. I'm not sure exactly how good you are aiming for or able to get near 20mpg with any setup. An ls swap might get you near with the correct tuning. I know it's not a chevy.... First time Ford buyer here now.... Don't worry, I found the support group. 2013 F-150 4wd supper crew with a 4 inch lift and 36"x13" tires on 18" wheels for now. It's the 5.0, tuned it myself with HPtuners and I'm getting 21 mpg with 93 octane/No ethanol! on the highway running 80mph. Much more then that, it drops fast.

[donut]

My thoughts are similar to rich weyand's, though, If you can tune, carb and TBI mileage may be closer.

An '87 I drove, with a 350, tbi and OD, would get 13. Unknown rear gears, but with BF Goodrich AT TA's, which I believe were 33".

Sig trucks were 11 and 13 respectfully.

[cdub2010]

A lot of granny drivers here. I seriously doubt you will get any better than 10mpg on any of those. I know I never have done better than 10 mpg on any lifted square body. Big heavy tires and big lift add crappy mpg. Good luck keeping your foot out of the gas with any of those engines.

[Bigstevex4]

Originally Posted by cdub2010

A lot of granny drivers here. I seriously doubt you will get any better than 10mpg on any of those. I know I never have done better than 10 mpg on any lifted square body. Big heavy tires and big lift add crappy mpg. Good luck keeping your foot out of the gas with any of those engines.

Aint that the truth i have a 90 blazer 4 inch lift 36 inch1050s 410 gears TBI 10 on a good day hway. I hear these stories of 25 mpg in a full size pickup.2015 Chevy only claims 24 with a v6 in a std cab pickup and thats perfict condistions. Any time you lift some thing add taller tires your pushing a house down the freeway. I Ride a bike alot and have for 40yrs on the street aint nothing on the rode that mucks up the air like full size pickup.

[donut]

Originally Posted by cdub2010

A lot of granny drivers here. I seriously doubt you will get any better than 10mpg on any of those. I know I never have done better than 10 mpg on any lifted square body. Big heavy tires and big lift add crappy mpg. Good luck keeping your foot out of the gas with any of those engines.

On my 2 rigs they were with stock size suspension and tires. Yep, granny driver here. Over the years, tickets have made my insurance go up $$$

My '86 is really efficient now. Blew motor a couple weeks ago....

[andrewmp6]

Diesel may cost more at the pump but you will get more mileage out of that gallon then gas.I rather keep a 1 ton all 1 ton you can haul more and run a lot bigger tires later on.The 1/2 ton axles are good tell 37s the 1 tons 44s.

[AntiGov]

I get 12 mpg on road trips cruising speed 55/60 ..........90 v3500 crew cab stock 350 tbi with headers and dual exhaust , th400 , 4:10 gears, 6 inch lift , 37" tires.