I've got an older Chevy 3/4 4x4 w/ sb 400 and the original Rochester carb. The engine /truck has aprox 100k on it total. It runs pretty good for the most part but was thinking it is time to revive it a little, plus I was looking for better fuel economy. It cxurrently gets about 8 mpg city and 10-11 hwy. Someone told me headers would help. The original carb is still on it and hasn;r been touched -same w/ the engine. My grandpa bought it in '78 -sold it to my dad in '94 andi bought it from him 2 yrs ago. The body's pretty straight and other than a new exhaust manifold. The engine is untouched. I think it has the "heavy" transfer case and the turbo 400 tranny. It burns a little oil ( 1qt per 4 tanks fuel. It has sat for periods of several months at time because it was reserved for carrying a camper or hauling horses periodically. I think the valve guides are worn and allowing the oil to seep through and be burned. ? is should I have the original carb rebuilt or put on a Holley or other. I was thinking about having the top end done- valve job basically to stop the oil burning, but some one told me to just buy new heads. Any ideas to my dilema(s). I do regular maintenence myself but the car thing scares me. I could probably rebuild it ,but don't have a clue how to adjust one. Not even sure if its a manual ,automatic, or electric choke.

You would know if it was a manual choke or not, there would be a little knob in the cab that you have to pull before start up, it would be labled choke. You have an electric choke.
Headers will help but not really enough to make a noticble difference.
Burning a qrt of oil every four tanks is a lot IMO, valve guides would help but might be a piston ring problem too. Having the heads redone really wouldnt do much to help your economy either, a newer set of heads would probably be the best way to go in that regard.
I cant remember what size carb came with your engine but if you put a smaller CFM carb on the motor, that would really help your economy, however it will hurt your top end performance, if you put a 2 barrel carb on it you will get a noticable gain in economy. Smaller tires would also help that situation or a taller gear set up would help too.
If you were really serious about getting some better economy out of that motor, an EFI swap would make the most difference. Maybe slap on an Edelbrock throttle body, this basically replaces your quadrajet carb. You might have to replace your fuel pump too though.
Simple things to do would be to check your fuel filters. Replace your spark plugs, wires, cap and rotor. Maybe throw in some octane booster to clean out any carbon deposit build up.
Your problem is you have a brick of a truck, it dosent cut air, it pushes it out of the way. You also have a decent sized engine, they like their fuel. Your truck is anything but lite. So you have a big heavy vehicle pushing a lot of air with a fuel hungry motor, your not going to be able to do much to improve your fuel economy IMO.

Keep the Q-jet, rebuilt if neccesary.

That truck should have a 203, full time t-case. If it hasn't been converted to part time, do so.

Pete

The t-case has five positions -from the top(forward) towards the seat it goes -4low-2low-neutral-2hi-4hi. It has a set of "rough country" locking hubs.
They turn almost a complete revolution from "free" to "lock". A friend of a friend told me it was the heavy duty t-case w/ the gears in it instead of being chain driven. I don't remember what style he said it was. I assume it was a 205 or 208 (NP)? The Edelbrock throttle body sounds interesting. My old '85 Ford Crown Vic Wagon had a little 302 w/ a throttle body in it and It ran like a dream and got around 20 mpg. Not bad for a full sized wagon.

Fuel injection vs a good running stock carb won't make that much difference. If that motor is running the 441 heads they are just fine for a stock 400. Nothing in the aftermarket can touch those for a stock application. You could change to vortec's, but this would require possible piston changes ect.
I really think the best thing you could do would be to have someone rebuild that motor for you.
Newer cars today get mileage from overdriven gear ratio's that keep the rpm's down. You could get 10% better mileage with injection after spending at least $1500.00. That will buy quite a bit of fuel. As for the old tired carb. Buy a new replacement they make, and use the jets and metering rods from the one you have. Q-Jets are 750 cfm carbs, but GM has them limited by a rod on the secondaries to 590 cfm. It is by far the best all around carb going. The old Dodge Carters they now call Edelbrocks are loser carbs for those who can't figure it out themselves.

My 2005 double lay-me-down port-fuel injected vortec latest and greatest state-of-the-art no-distributor direct-plug ignition closed loop EPA certified wind-tunnel tested OEM enhanced-chip Chevy Suburban 8.1L gets exactly the same mileage as your old 78 chevy.

You aren't missing much !

you have an np203, even though you have slectable hubs you need to convert the internals of the case. If your friend knows what he is talking about then you have an np205. I would check just to be sure though. Even though the hubs are unlocked you are still spinning the front and read diff going down the road which is more drag on the motor cause worse fuel milege.

Also lookinto a after market exhaust, tune up the engine, get some BG 44K and clean out the carbon deposits, and get the engine rebuilt. I doubt you will see better then 14 at anytime with that truck though. Its not a honda after all.

If you are going to do a efi swap, stock TBI setups are easy swaps, and should run you a few hundred bucks if you get most all of the parts used. You may need to have a chip burned for the 400 though.


Pete