Would it be worth it?

[Toe_cutter]

Doing some research today I found some specs on the read end in my truck, it weighs in at over 550lbs!!!! It is a 3/4 ton, but that still seems excessive to me. There are two lighter duty options that would bolt right in (only changing the u joint) that are considerably less weighty, 200lbs and 230lbs. I have worked really hard with mods and driving habits to get from 15 hwy stock to 21-22 combined. If I decide to do the swap I could try and find one with more hwy friendly gears, I have 3.73 now, maybe a 3.08 or 2.something. Worth the trouble and expense?

[Sven7]

I imagine the gear ratios would help more. Weight reduction has its place when accelerating but probably won't do much at all for cruising. A higher top gear will help you whenever you're using it- that is, whenever you're driving on a highway!

[Frank Lee]

You have a "warm air intake" and no gas logs. Not much to go on. :/

[gone-ot]

...the EPA claims 1-2% improvement in MPG for every 100 lbs reduction in 3,000 lb range vehicles, so a 300 lb reduction (550-250) should be worth about 3-6% improvement.

...however, the 3.08:1 axle ratio will net a BIGGER improvement, for sure, although your "load-hauling" capabilities will go down.

[Toe_cutter]

Yeah, I haven't gotten around to updating my stats on here as of yet. A quick rundown on my truck would be......93 Chevy C2500, TBI 350, 4l80e, and 14 bolt semi-floating rear with 3.73 gears.
Mods are warm air intake, full tune up with plugs gapped to 52 and timing advanced 4* btdc, new 4.3 injectors ( smaller with less flow at stock fuel pressure), adjustable fuel pressure regulator running 5psi over stock pressure (with the smaller injectors I get almost the same flow as stock but it is a much finer spray that atomizes much better), K&N 3x14 element, stock y pipe with 3" pipe and high flow cat with turbo muffler ran to just before the rear axle, underdrive pulleys and twin electric fans wired to two toggle switches so I can engage them one or both at a time when needed. Also I found a set of 15 inch alloy wheels to replace the stock 16's, with 245/75/16's they weighed around 90lbs ( will get more accurate measurements). Now I'm running 235/75/15 because they are a third the price, narrower, don't look tiny, and tires and wheels weigh right at 50lbs each. They also lower the vehicle about an inch.

[Toe_cutter]

Also I moved my road box to the back of the bed butted up against the tailgate, and slip my tool box right up behind that to try and simulate a partial bed cover, I don't think it helped with economy but it makes a nice work area when the tailgate is down.

[dennyt]

Have you corrected your speedometer / odometer for the smaller tires? That will affect your actual vs. indicated miles per gallon.

[Toe_cutter]

Yeah, measured the circumference of new and old tires to get an accurate measurement of the difference, then figure that in to the mileage listed on my "gas notebook"