better gas milage questions

Whatever you do, weight out the costs vs. the benefits.

For example: lets say you get 10 mpg now, just for nice round numbers. Fuel is $4/gal. So it cost you $4 to drive 10 miles, or 40 cents/mile.

So you decide to spend $300 on a programmer that claims to give you a 10% increase in mileage (not really likely, but we'll run with it). So 10 mpg + 10% = 11 mpg. $4 fuel means $4 gets you 11 miles now, or 36.36 cents/mile.

You spent $300 to save 3.64 cents/mile. $300/[$0.0364/mi] = 8242 miles before you break even on your investment.

Some "mpg mods" have an even worse ROI.

Best bet if you want to drive that beast is to make sure it's getting into closed loop and operating properly. And the usual... make sure your tires are properly inflated and your filters/injectors are clean, etc.

I do the park it choice. Mine sets in my garage 80% of the time & I drive my Harley truck. And get the dually out on weekends to run errands in or just to get it out every now and then.

Absolutely, something I find myself pointing out a lot. However...! When the upgrade involves re-gearing or swapping to an overdrive transmission, either of which being pretty expensive, you also have to consider not just the MPG potential but the decrease in wear and tear on the engine. Hard to measure, sure, but you pretty much can guess that dropping cruise RPM's significantly is probably really good for the engine, as long as you don't go so far that you're lugging it around.

Richard

Very good points ^

Especially if you plan on keeping the truck for a very long time.

Excellent points and comments. Thanks everyone. So I picked up with my dually with headers, CAI, and program so... The ROI for me may be a little different.

The takeaway from all of this discussion is that I will have to either bring another one of my vehicles out from Fl. or buy something else for a daily driver. Decisions, decisions.

Finding a place close to work will help.

Drop a gen III fuel injected engine and T56 in that elco! That will get you some good mileage

If your truck will take it, bump the timing up a couple degrees. I have an aftermarket standalone EFI setup myself. You can tune for MPG and HP at the same time. I run lean with tons of timing on a light load, and fat with moderate timing on a load. I'm not a Bowtie guy but I'm sure there Is a way to reprogram you computer...

The cost and ROI of the OD swap is actually excellent if you do it right. First read up on how to determine the year and condition of the OD trans you're looking for. Then hit up the local pull-your-own-parts salvage yards until you find what you want. Once you're sure, then don't just pull it, but aksp pull the crossmember, the front half of the driveshaft, and whatever else is different. The 700R-4 needs the TV cable and bracket.
Swapping an NV4500 in place of a stupid SM465 is about the same deal as putting an '88-'93 5.7L version of the 700R-4 in place of a stupid TH400.
I did exactly this to my '78 Camaro, which had been giving 8 MPG no matter what I tried. I spent about $100 on the trans, another $100 on getting the driveshaft shortened, then the shift kit, lockup kit and shipping added another $150. New filter and fluid put me at $400 then, which would be $500 now.
After the swap, I saw 25.1 MPG at a steady 65 MPH. I didn't change the carb or anything else that could explain it. The only explanation is that I got my cruise out of the Q-Jet's main metering circuit so I was then cruising on the idle circuit.
Still, It paid for itself right away. And these days, there's so much online help that you no longer need to buy a lockup kit.
Lastly, my 25.1 was with my centrifugal advance frozen. I finally figured that out and fixed it, only to sell the car a week later, before I could prove it would then do 27 MPG at 60 MPH.

^^^^
Hold your horses partner, it may not have over drive but I wouldn't call a th400 stupid. To this day it gets swapped into all sorts of non-GM vehicles because they are TOUGH.

Th400s are a beast I have one in my dually, my 68 c10, and my 78 camaro with correct gearing u can get mileage. And not to step on ur story but I had a 01 camaro with a gen III ls1 with a t56 and a 3.42 gear and only got 22mpg so idk how ur carbbed camaro would get 25.1