Sunday, November 13, 2011

What is the most fuel efficient engine I can replace a 1990 Chevrolet 350 with in my 4wd z71 stepside truck?

Need to replace engine AND transmission in my 1990 4wd chevrolet 71 stepside pick up truck. This is daily driver, never needing anymore towing power than necessary to pull a trailer full of mulch home to the garden. I generally want to reduce fuel costs as much as possible and must keep 4wd, but don't need speed or power beyond what a trailer of mulch requires. What engine and transmission combination do you recommend for this vehicle?|||Best to replace it with what you have.





The 350 is a perfect blend of power and economy for a full-size truck. Any smaller and the motors must work too hard to get the vehicle moving (bad mileage at that time influences the possible better mileage at cruise. Any larger and you start losing economy solely because of displacement. With no requirement to tow anything extremely heavy, the larger displacement just isn't necessary.





If you swap motors, you start running into other issues which add cost (PROM, potential wiring differences, fan shrouds, etc) and will likely take tens of thousands of miles to pay off before any sort of cost savings from economy can become possible.





On the transmission side, a manual transmission would be an excellent choice (NV4500...5 speed overdrive), as they don't fail, and ALWAYS provide higher mileage than a similarly geared automatic.





However, as with the engine swap, you start running into additional cost (again, PROM, pedal assembly, cutting hole for shifter, drivelines, etc) that will take forever to recoup.





It's just easier to stay with what you had to start with.|||Best bang for buck - Fuel injected 305, either 4 speed automatic, or manual tranny


More efficient yet - 5.3 w/ 4 speed auto or manual tranny.





The best thing to save gas mileage is to sell it and buy an s-10 or a something like it.|||efi 350 and the thm 700r4. my father has that truck ion a 2wheel drive, drives it like it was a 4 wheeler. no problems.

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