Can I get more MPG out of my 350?

[Elpresidente]

I'm kind of going back to an old topic on this one, now i've got everything worked out.
Brand new GM goodwrench crate 350, about 6000 miles on it. Edelbrock Performer 600 carb (#1406), changed the rods & jets 1.5 stages leaner in power & cruise modes (changed: jets .098 to .095, rods .075x047 to .073x047)  and an Edelbrock performer intake.
Engine is set at 8 degrees BTC, distributor is factory stock from my old 305. I don't have much more information on that.
Engine has headers and dual exhaust, also running a 700R4 and 3.08 gears out back.
I'm currently getting 11.75 MPG, is there anything else I can do to improve mileage?

*I haven't touched the AFR screws.

[jaredts]

Go through the complete tuning procedure for your carburetor.  The screws on the front of the carburetor only adjust mixture when you're idling, but they should be set to highest rpm or greatest vacuum.  As far as leaning out a 1406, I don't see how you get away with that.  They are very lean from the factory.  Compare its jets and rods to the 1405 or some other carburetors out there.  How does it run?  Does it backfire through the carburetor?  Checked for vacuum leaks?  A little more timing advance will help a little.  What kind of truck are we talking about?  Is this an esc distributor?  Is the lockup and 4th gear working on the 700r4?  Have you checked the plugs since installing the engine?  Are you running a cat?

Give me a few more minutes to come up with more questions!

[velojym]

Also, energy management while driving, if you aren't already practicing it, oughta help a bit. Let off the gas just before cresting a hill, try to time the traffic lights if possible, stuff like that. A light right foot can easily make a mile or two difference.
Also, a 2/3 bedcover over the *back* part of the bed, leaving the front of the bed open to maintain a vortex, seems to help aerodynamically, and that combined with a deflector mounted to the back of the cab roof, angled down about 13 degrees, was found to create an interestingly large drag reduction.
ecomodder.com has a few threads on pickup drag.

I wouldn't go into hypermiling, though. It might greatly improve mpgs, but I really don't want to spend all my trips leading a convoy of ticked-off drivers.

[Elpresidente]

Truck is an '82 C10.
It runs well, no backfiring (adjusted the choke, solved that problem) No vacuum leaks and I advanced the timing 2 more degrees.
The distributor is esc, and i'm unsure about the lockup on the transmission. I'm assuming it does work, It's a freshly rebuilt trans and has no issues.
No cats on this truck, just dual pipes and thrush turbos.

[Irish_Alley]

keep it below 60. i have sm465, 38s and 4.10 i can get about 10 if im good

[jaredts]

It might not help, but I would get rid of that esc distributor and get a regular hei.  Something is wrong I just don't know what.  Your truck should get better than that.

[zieg85]

It might not help, but I would get rid of that esc distributor and get a regular hei.  Something is wrong I just don't know what.  Your truck should get better than that.

X2 ditch that distributor.  What you are looking for is a light grey at the exhaust pipes.  You can probably stand to advance the timing further.  I used to run 32 degrees total advance without a problem in my 72. 

[bobcooter]

Some guys on here were buying these a while back. I haven't heard anything negitive. But I went for period where I wasn't on here too much also.  Someone please correct me if I'm wrong. It seems like the price went down even further.
http://www.skipwhiteperformance.com/detail.aspx?Item=6500-GY

[Elpresidente]

Distributor looks like the next step, we'll see what happens. thanks!

[slammed79]

I'd lean towards the distributor as well. I was getting twelve on an older tune up,  and leaky carb. With a freely rebuilt qjet, plugs and wires, I pull 14.5 in town and about 18-19 on the freeway.

[Jason S]

Along with a new distributor, you might look at the springs, weights and vacuum advance on the distributor and "tune" the distributor. 

[1980c10]

I had my engine dyno tuned and found that an open spacer between the carb and intake really evened out the a/f ratio between banks.
btw a dyno tune is never a bad idea. IMO the best couple hundred spent on my truck. Better than theories from anywhere when you can read it on a printout. Gained myself 20 hp and probably some mpgs as well.